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On the normal behaviour of partially elliptic lower dimensional tori of hamiltonian systems

Abstract

The purpose of this paper is to study the dynamics near a reducible lower dimensional invariant tori of a finite-dimensional autonomous Hamiltonian system with $\ell$ degrees of freedom. We will focus in the case in which the torus has (some) elliptic directions. First, let us assume that the torus is totally elliptic. In this case, it is shown that the diffusion time (the time to move away from the torus) is exponentially big with the initial distance to the torus. The result is valid, in particular, when the torus is of maximal dimension and when it is of dimension 0 (elliptic point). In the maximal dimension case, our results coincide with previous ones. In the zero dimension case, our results improve the existing bounds in the literature. Let us assume now that the torus (of dimension $r$, $0\le r<\ell$) is partially elliptic (let us call $m_e$ to the number of these directions). In this case we show that, given a fixed number of elliptic directions (let us call $m_1\le m_e$ to this number), there exist a Cantor family of invariant tori of dimension $r+m_1$, that generalize the linear oscillations corresponding to these elliptic directions. Moreover, the Lebesgue measure of the complementary of this Cantor set (in the frequency space $\RR^{r+m_1}$) is proven to be exponentially small with the distance to the initial torus. This is a sort of ``Cantorian central manifold'' theorem, in which the central manifold is completely filled up by invariant tori and it is uniquely defined. The proof of these results is based on the construction of suitable normal forms around the initial torus.

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On the normal behaviour of partially elliptic lower dimensional tori of hamiltonian systems

Author: Jorba, Angel,Villanueva Castelltort, Jordi
Year: 1996
Source: https://upcommons.upc.edu/bitstream/2117/931/1/9602jorba.pdf
On he No mal Beha iou o Pa ially Ellip ic Lowe
Dimensional To i o Hamil onian Sys ems

Angel Jo ba and Jo di Villanue a
Oc ob e 16 h, 1996
Depa amen de Ma ema ica Aplicada I
Uni e si a Poli ecnica de Ca alunya
Diagonal 647, 08028 Ba celona, Spain.
E-mails:
[email p o ec ed]
,
[email p o ec ed]
Abs ac
The pu p ose o his pap e is o s udy he dynamics nea a educible lowe dimen-
sional in a ian o i o a ni e-dimensional au onomous Hamil onian sys em wi h
`
deg ees o eedom. We will o cus in he case in which he o us has (some) ellip ic
di ec ions.
Fi s , le us assume ha he o us is o ally ellip ic. In his case, i is shown
ha he diusion ime ( he ime o mo eaway om he o us) is exp onen ially big
wi h he ini ial dis ance o he o us. The esul is alid, in pa icula , when he
o us is o maximal dimension and when i is o dimension 0 (ellip ic poin ). In
he maximal dimension case, ou esul s coincide wi h p e ious ones. In he ze o
dimension case, ou esul s imp o e he exis ing b ounds in he li e a u e.
Le us assume now ha he o us (o dimension
, 0

< `
) is pa ially
ellip ic (le us call
m
e
o he numb e o hese di ec ions). In his case we show ha ,
gi en a xed numbe o ellip ic di ec ions (le us call
m
1

m
e
o his numb e ),
he e exis a Can o amily o in a ian o i o dimension
+
m
1
, ha gene alize he
linea oscilla ions co esp onding o hese ellip ic di ec ions. Mo eo e , he Leb esgue
measu e o he complemen a y o his Can o se (in he equency space
R
+
m
1
)
is p o en o be exp onen ially small wi h he dis ance o he ini ial o us. This is
aso o Can o ian cen al mani old" heo em, in which he cen al mani old is
comple ely lled up byin a ian o i and i is uniquely dened.
The p o o o hese esul s is based on he cons uc ion o sui able no mal o ms
a ound he ini ial o us.
2
Con en s
1In o duc ion 3
2 Summa y 4
2.1 No a ion and o mula ion o he p oblem . . . . . . . . . . . . . . . . . . . 4
2.1.1 Reducibili y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.2 Linea no mal b eha iou o he o us . . . . . . . . . . . . . . . . . 5
2.1.3 Semino mal o m: o mal desc ip ion . . . . . . . . . . . . . . . . . 6
2.2 Resul s and main ideas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2.1 Semino mal o m: bounds on he emainde . . . . . . . . . . . . . 8
2.2.2 Ellip ic o i a e e y s icky . . . . . . . . . . . . . . . . . . . . . . . 8
2.2.3 Can o amilies o in a ian o i . . . . . . . . . . . . . . . . . . . . 9
3 No mal o m and eec i e s abili y 11
3.1 No a ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.2 Bounding he emainde o he no mal o m . . . . . . . . . . . . . . . . . 12
3.3 Eec i e s abili y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4 Es ima es on he amilies o lowe dimensional o i 23
4.1 Nondegene acy condi ions . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.1.1 Nondegene acy o he in insic equencies . . . . . . . . . . . . . . 24
4.1.2 Nondegene acy o he no mal equencies . . . . . . . . . . . . . . . 26
4.2 Main heo ems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.3 P o o o Theo em 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
4.3.1 P elimina ies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.3.2 The i e a i escheme . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.3.3 Con e gence o he i e a i escheme . . . . . . . . . . . . . . . . . . 37
4.3.4 Bounds on he measu e . . . . . . . . . . . . . . . . . . . . . . . . . 38
5 Basic lemmas 40
6 Acknowledgemen s 44
Re e ences 44
A. Jo ba and J. Villanue a
3
1In o duc ion
The s udy o he solu ions close o an in a ian ob jec is a classical sub jec in Dynamical
Sys ems. He e we will add ess he p oblem o desc ibing he phase space nea an in a ian
o us o a Hamil onian sys em. To x he no a ion, le us call
H
o a eal analy ic
Hamil onian wi h
`
deg ees o eedom, and le us assume i has an in a ian
-dimensional
o us, 0


`
. No e ha we a e including he wo limi cases, ha is, when i is an
equilib ium p oin and when i is a maximal dimensional o us.
To s a he discussion, le us assume ha he o us has some ellip ic di ec ions, his
is, ha he linea ized no mal ow con ains some ha monic oscilla o s. A na u al ques ion
is i hese oscilla ions p e sis when he nonlinea pa o he Hamil onian is added. I he
o us is o ally ellip ic, ano he na u al p oblem is he (nonlinea ) s abili y a ound his
o us.
The e a e known answe s o hese ques ions in some conc e e cases. I
= 0 ( he o us
is an equilib ium p oin ) and i is o ally ellip ic, KAM heo y says ha he e is plen yo
maximal dimension in a ian o i a ound he poin (see 6]): he complemen a y o he
se o in a ian o i has measu e exp onen ially small wi h he dis ance o he poin . I
is well known ha i
`
=2, he maximal dimensional o i spli he ene gy le els
H
=
h
in disconnec ed comp onen s. This is he basis o p o e he nonlinea s abili y o he
poin . Un o una ely, i
` >
2, he in a ian o i do no sepa a e he ene gy le els. In
his case i is gene ally b elie ed ha some diusion can ake place in he phase space (see
2]). Ne e heless, i is s ill p ossible o gi e lowe bounds on he diusion ime, ha a e
exp onen ially big wi h he dis ance o he poin ( hey ollow immedia ely om 6]).
I
=
`
( he o us has maximal dimension) we can no sp eak ab ou no mal b eha iou
since he e a e no a ailable di ec ions". The nonlinea s abili y has b een s udied in 14]
and 13] (among o he s), whe e i is shown ha he diusion ime is also b ounded by an
exp onen ially big (wi h he dis ance o he ini ial o us) quan i y. In 13] i is also ela ed
his exp onen ially big s abili y ime wi h he densi y o in a ian maximal dimensional
o i a ound he ini ial one, by showing ha he o al measu e o he gaps be ween he
in a ian o i nea by is no bigge han an exp onen ially small quan i y wi h esp ec o
he dis ance o he ini ial one. In ac , in 13] i is p o ed ha unde an ex a s eepness
condi ion he diusion ime is, a leas , sup e exp onen ial. This condi ion co esp onds
o he classical quasi-con exi y hyp o hesis used o ob ain global" and exp onen ially big
s abili y ime o a p e u b ed in eg able Hamil onian sys em wi h esp ec o he size o
he p e u ba ion (see 5] and e e ences he ein).
In his wo k we will conside hese p oblems, wi hou any s eepness condi ion, o a
lowe dimensional o us. The wo limi cases men ioned ab o e a e included, and he esul s
ob ained can b e summa ized as ollows: o a o ally ellip ic o us, weha e ob ained lowe
bounds o he diusion ime. They ag ee wi h he bounds o 13] in he case
=
`
bu ,
o he case
=0, hey a e b e e han he ones di ec ly de i ed om 6]. Mo eo e , we
show he exis ence o quasip e io dic solu ions ha gene alize he linea oscilla ions o he
no mal ow o he comple e sys em. I he o us has no mal b eha iou o he kind some
cen es"

some saddles" we ob ain, o any combina ion o cen es, a Can o amily o
in an o i a ound he ini ial one, by adding o he ini ial se o equencies new ones ha
come om he nonlinea oscilla ions asso cia ed o he chosen cen es. Those in a ian o i
ha e he same no mal b eha iou as he ini ial one (o cou se, skipping he cen es ha
gi e ise o he amily). This esul is a so o Can o ian cen al mani old" heo em,
4
No mal Beha iou o Lowe Dimensional To i
in which we ob ain an in a ian mani old pa ame ized on aCan o se and comple ely
lled up byin a ian o i. We no e ha we ob ain a Can o ian cen al submani old" o
eachcombina ion o cen es, and ha i is uniquely dened.
The p o o s a e based on he cons uc ion o sui able no mal o ms. The es ima es on
he di ussion ime a e ob ained b ounding he emainde o his no mal o m, while he
exis ence o amilies o lowe dimensional o i is p o ed by applying aKAM scheme o
his emainde .
The pap e has been o ganized in he ollowing way: Sec ion 2 summa izes he main
ideas and esul s con ained in he wo k. Sec ion 3 con ains he de ails conce ning he
no mal o m and he bounds on he diusion ime. Sec ion 4 is de o ed o he exis ence
o amilies o o i nea he ini ial one and, nally, in Sec ion 5, we ha e included some
basic lemmas used along he pap e .
2 Summa y
He e we ha e included a echnical desc ip ion o he p oblem, he me ho dology used in
he p o o s and he esul s ob ained. Weha e ommi ed he echnical de ails o he p o o s
in o de o simpli y he eading.
2.1 No a ion and o mula ion o he p oblem
Le
H
b e a Hamil onian sys em o
`
deg ees o eedom dened on
R
2
`
,ha ing an in a ian
-dimensional iso opic o us ( ha is, he canonical 2- o m o
R
2
`
es ic ed o he angen
bundle o he o us anish), 0


`
,wi h a quasip e io dic ow gi en by he ec o o
basic equencies ^
!
(0)
2
R
. We assume, om he iso opic cha ac e o he o us, ha we
can in o duce (wi h a canonical change o co o dina es)
angula a iables
^

desc ibing
he ini ial o us. Hence, he Hamil onian in hese co o dina es akes he o m
H
(
^
 x
^
I y
)= ^
!
(0)
>
^
I
+
1
2
z
>
B
(
^

)
z
+
H
1
(
^
 x
^
I y
)

whe e
z
>
= (
x
>
y
>
). He e,
x
,
y
a e
m
-dimensional eal ec o s, and
^

,
^
I
b elong o
R
,
+
m
=
`
. O cou se,
^

,
x
a e he p osi ions and
^
I
,
y
he esp ec i e conjuga e momen a. As
^

is an angula a iable, we assume ha
H
depends oni ina2

-p e io dic way. Mo eo e ,
we will use
u
>
o deno e he scala p o duc o wo ec o s.
We also supp ose ha he Hamil onian
H
can be ex ended o a eal analy ic unc ion
dened on he se
D
m
(

0
R
0
) gi en by
D
m
(

0
R
0
)=
(
^
 x
^
I y
)
2
C

C
m

C

C
m
:
j
Im
^

j

0

j
z
j
R
0

j
^
I
j
R
2
0
g

(1)
whe e
j
:
j
deno es he inni y no m o a complex ec o (we will use he same no a ion o
he ma ix no m induced). The die en scaling o he a iables
z
and
^
I
in
D
m
(

0
R
0
)
is mo i a ed by he deni ion o deg ee o a monomial o he Taylo expansion (wi h
esp ec o
z
and
^
I
, see (10)) used along he pap e :
deg

h
ls
(
^

)
z
l
^
I
s

=
j
l
j
1
+2
j
s
j
1

(2)
A. Jo ba and J. Villanue a
5
wi h
l
2
N
2
m
,
s
2
N
, and whe e
j
k
j
1
is dened as
P
j
j
k
j
j
. The eason o coun ing
wice he exp onen
s
will b e clea la e (i is mo i a ed, basically,by he p op e ies o he
Poisson b acke ).
We assume he ini ial in a ian o us is gi en by
z
=0and
^
I
=0. Hence, we can ake
B
(
^

) as a symme ic 2
m
-dimensional ma ix, wi h eal co ecien s ha dep end on
^

in
analy ic and 2

-p e io dic way. Mo eo e , he Taylo expansion o
H
1
a ound
z
=0,
^
I
=0
b egins wi h e ms o deg ee a leas h ee.
2.1.1 Reducibili y
We will assume ha he no mal a ia ional ow a ound his o us (gi en by he ma ix
J
m
B
(^
!
(0)
), whe e
J
m
is he canonical 2- o m o
C
2
m
) can be educed o cons an co e-
cien s wi h a eal linea change o a iables ha dep ends quasip e io dically on
^

, ha ing
^
!
(0)
as a ec o o basic equencies (quasip e io dic Flo que educ ion).
1
The hyp o hesis
do es no seem o be e y es ic i e in ou con ex , since all he pa ially ellip ic o i
ob ained by KAM echniques ha e educible no mal ow (see, o ins ance, 7], 15], 8],
11]). This p op e y allows o cons uc a canonical change o co o dina es ha ans o ms
he ma ix
B
(
^

) o cons an co ecien s. Hence, we will assume ha
B
is a eal symme ic
ma ix, indep enden om
^

,and ha he ini ial Hamil onian in hose Flo que a iables
lo oks like:
H
(
^
 x
^
I y
)= ^
!
(0)
>
^
I
+
1
2
z
>
B
z
+
H
2
(
^
 x
^
I y
)

(3)
whe e
H
2
b egins wi h e ms o deg ee a leas h ee.
2.1.2 Linea no mal beha iou o he o us
We also assume ha he ma ix
J
m
B
has die en eigen alues, gi en by he complex ec o

2
C
2
m
, ha akes he o m

>
=(

1
:::
m

;

1
:::
;

m
) ( his s uc u e comes om
he canonical cha ac e o he sys em). We no e ha in his case, die en eigen alues also
means nonze o eigen alues. We will e e o hose eigen alues as he no mal eigen alues
o he o us. We ema k ha i

j
=
i
(wi h

2
R
n
0
g
and
i
=
p
;
1) is an eigen alue,
hen

j
+
m
=
;
i
. The ec o s o
R
2
m
ha a e combina ion o eigen ec o s co esp onding
o (couples o ) eigen alues o his o m a e called he ellip ic di ec ions o he o us.
The s udy o he b eha iou o he ini ial o us in hose di ec ions is he main issue in
his pap e . Mo eo e , he e may be o he eigen alues wi h eal pa die en om ze o,
ha dene he hyp e b olic di ec ions o he o us. They can be g oup ed in one o hese
wo ollowing o ms:
1. i

j
=

2
R
n
0
g
, hen

j
+
m
=
;

,
2. i

j
=

+
i
(wi h
 
2
R
n
0
g
), hen, om he eal cha ac e o he ma ix
B
,
we can ake

j
+1
=

;
i
,and hence,

j
+
m
=
;

;
i
and

j
+
m
+1
=
;

+
i
.
The imagina y pa s o he eigen alues a e usually called no mal equencies o he o us.
Fo easons ha will b e clea la e , i is e y con enien o pu he ma ix
J
m
B
in diag-
onal o m. This is p ossible wi h a complex canonical change o basis, ha ans o ms he
1
I he o us is educible excep by an small emainde , i is s ill p ossible o de i e simila esul s (by
adding a pe u ba i e pa ame e ). See 9] and 11] o he main ideas and ela ed esul s.

6
No mal Beha iou o Lowe Dimensional To i
ini ial eal Hamil onian sys em in o a complex one. Thus, he complexied Hamil onian
has some symme ies b ecause i comes om a eal one. As his symme ies a e p ese ed
by he ans o ma ions used along he p o o s, he nal Hamil onian can be ealied. In
ac , complexica ion is no necessa y, bu i simplies he p o o s. Ne e heless, in he
p o o s we ha e no w i en explici ly he p ese a ion o hose symme ies. This is be-
cause he de ails a e e y edious and cumb e some and, on he o he hand, he in e es ed
eade should no ha e p oblems in w i ing hem (i is a e y s anda d me ho dology).
Fo u he uses, we deno e by
Z
>
=(
X
>
Y
>
) hose complex (canonical) a iables, and
by
B

he complex symme ic ma ix such ha
J
m
B

=diag(

).
2.1.3 Semino mal o m: o mal desc ip ion
Now we ake a subbundle o
R
2
m
,
G 
R
2
m
,in a ian by he ac ion o he ma ix
J
m
B
,
and such ha i only con ains eigen ec o s o ellip ic yp e. We pu 2
m
1
= dim(
G
)
(we ecall ha his dimension is always e en) and we call ~
!
(0)
2
R
m
1
o he ec o o
no mal equencies asso cia ed o his subbundle. As
G
will b e xed along he pap e , we
in o duce some no a ion ela ed o i . Fi s , we assume ha he  s
m
1
eigen alues o

a e he ones asso cia ed o
G
, ha is,

j
=
i
~
!
(0)
j
,
j
= 1
:::m
1
. We also deno e by
^

2
C
2(
m
;
m
1
)
he ec o ob ained skipping om

he 2
m
1
eigen alues asso cia ed o
G
.
This in o duces in a na u al way he decomp osi ion
X
>
= (
~
X
>

^
X
>
),
Y
>
= (
~
Y
>

^
Y
>
),
ob ained aking apa he  s
m
1
comp onen s om he las
m
;
m
1
.Mo eo e , we dene
~
Z
>
= (
~
X
>

~
Y
>
) and
^
Z
>
= (
^
X
>

^
Y
>
). A simila no a ion can be used o any ec o
l
2
N
2
m
, spli ing
l
>
= (
l
>
X
l
>
Y
), whe e
l
X
and
l
Y
a e he exp onen s o
X
and
Y
in he
monomial
Z
l
(
Z
l
=
X
l
X
Y
l
Y
). Then, we in o duce
!
(0)
2
R
+
m
1
as
!
(0)
>
=(^
!
(0)
>

~
!
(0)
>
),
and we ask o a Diophan ine condi ion o he ollowing o m,
2
j
ik
>
!
(0)
+
l
>
^

j

j
k
j

1
 k
2
Z
+
m
1
n
0
g
 l
2
N
2(
m
;
m
1
)

0
j
l
j
1

2

(4)
b eing
>
0 and
>
+
m
1
. This non esonance condi ion allows o cons uc ( o mally)
a semino mal o m ela ed o he chosen
G
.I we exp ess he Hamil onian in e ms o
he a iables
Z
, his semino mal o m is done by emo ing om
H
he monomials o he
ollowing o m (see (11) o he no a ions):
h
lsk
exp (
ik
>
^

)
Z
l
^
I
s
 l
2
N
2
m
 s
2
N
 k
2
Z

j
k
j
1
+
j
l
X
;
l
Y
j
1
6
=0

j
^
l
j
1

2

(5)
whe e
^
l
is he pa o
l
ha co esp onds o
^

. A e his no mal o m p o cess, using he
p ese a ion o he symme ies ha come om he complexica ion, we can ew i e his
( o mal) semino mal o m, in e ms o sui able eal a iables, in he ollowing o m:
H
(
^
 x
^
I y
)=
!
(0)
>
I
+
1
2
^
z
>
^
B
^
z
+
F
(
I
)+
1
2
^
z
>
Q
(
I
)^
z
+
O
3
(^
z
)

(6)
whe e, o simplici y,wedono change he name o he Hamil onian, and whe e we ex end
he decomp osi ion in o duced ab o e o he a iables (
x y
). He e, he ma ix
^
B
is a eal
2
The Diophan ine condi ion can b e elaxed when
j
l
j
1
=2and
l
>
^

only in ol es hyp e b olic eigen alues.
In his case, he esul s a e p o ed using a combined me hod based on a xed p oin scheme o he
hyp e b olic di ec ions and a New on me ho d o he emaining ones. This echnique allows o ha e
mul iple hype b olic eigen alues.
A. Jo ba and J. Villanue a
7
symme ic ma ix ob ained by p o jec ing
B
on he di ec ions gi en by he eigen alues
co esp onding o he eigen ec o s
^

.
I
is a compac no a ion o
I
>
=(
^
I
>

~
I
>
), whe e he
ac ions
~
I
can b e aken as
~
I
j
=
1
2
(
x
2
j
+
y
2
j
),
j
=1
:::m
1
,i wecho ose he eal no mal o m
a iables (
x y
) asso cia ed o he conside ed ellip ic di ec ions in adequa e (and s anda d)
way (see (44) in he p o o o Theo em 2). O cou se,
F
=
O
2
(
I
)and
Q
=
O
1
(
I
).
Now, we p o ceed o desc ib e he no mal b eha iou o he o us de i ed om his semi-
no mal o m. I is no dicul o check ha weha e he ollowing ( o mal) quasip e io dic
solu ions o he canonical equa ions o (6):
^

(
) =

^
!
(0)
+
@
F
@
^
I
(
I
(0))
!
+
^

(0)

^
I
(
) =
^
I
(0)

~
x
j
(
) =
q
2
~
I
j
(0) sin

~
!
(0)
+
@
F
@
~
I
j
(
I
(0))
!
+
~

j
(0)
!

(7)
~
y
j
(
) =
q
2
~
I
j
(0) cos

~
!
(0)
+
@
F
@
~
I
j
(
I
(0))
!
+
~

j
(0)
!

^
z
(
) = 0
:
Tha is, we ob ain a 2(
+
m
1
)-dimensional in a ian mani old (^
z
= 0) olia ed by a
con inuous (
+
m
1
)-dimensional amily o (
+
m
1
)-dimensional in a ian educible o i,
pa ame ized by
I
(0). The selec ion o he pa ame e
I
(0) is na u al, as
I
1
:::I
+
m
1
a e  s in eg als o he Hamil onian (6) es ic ed o he in a ian mani old ^
z
=0. We
ema k ha he o i o he amily collapse o lowe dimensional ones when any o he
~
I
j
(0)
b ecome ze o. In pa icula , i we ake
I
(0) = 0 we eco e he ini ial
-dimensional one.
In ac , o e e y 0

m
2

m
1
weha e, o his semino mal o m,

m
1
m
2

die en (
+
m
2
)-
dimensional amilies o (
+
m
2
)-dimensional in a ian o i. They a e asso cia ed o e e y
in a ian eal subbundle con ained in
G
. The skele on o hese amilies comes om he
na u al
-dimensional amily o
-dimensional o i con aining he ini ial one. This amily
is asso cia ed o he neu al di ec ions o he o us ( he neu al di ec ions a e conjuga ed
o he angen ones), an i is ob ained aking
G
= 0 in ou no a ion. Mo eo e , we also
ema k ha in (7) we only ha e eal o i when all he
~
I
j

0. This comes di ec ly om
he deni ion o
~
I
as a unc ion o he eal no mal o m a iables. To explain his ac le
us gi e he classical example o a 1-dimensional p endulum nea he ellip ic equilib ium
poin , 
x
+ sin(
x
)=0. The linea (no mal) equency a he equilib ium p oin is1. Mo ing
he ene gy le el in he eal phase space we ob ain p e io dic o bi s wi h equency smalle
han 1. I one wan s p e io dic o bi s wi h equency bigge han 1, one is o ced o ex end
he phase space om
R
2
o
C
2
, keeping he ime in
R
.This same phenomenon happ ens
when we s udy he no mal ellip ic di ec ions o a o us. I is imp o an o no e ha , o
us, a
s
-dimensional complex o us is a map om
T
s
o
C
2
`
. Hence, we will use he wo d
dimension" o e e o he eal dimension.
2.2 Resul s and main ideas
A basic esul in his pap e is he quan i a i e e sion o he semino mal o m, i we
only kill he monomials like (5) up o some ni e o de . F om he es ima es on his
semino mal o m, we deduce (unde ce ain nondegene acy condi ions) ha he no mal
8
No mal Beha iou o Lowe Dimensional To i
beha iou o he ini ial o us desc ib ed in Sec ion 2.1.3 is co ec " in he sense o he
classical KAM ideas: he ma jo i y" o hese o i eally exis (bu sligh ly de o med) in
he ini ial Hamil onian sys em. Mo eo e , we also deduce he long ime eec i e s abili y
o any eal a jec o y close o a o ally ellip ic o us. In he ollowing sec ions we p esen
he explici desc ip ion o hose esul s, and we explain he main ideas used in he p o o s.
2.2.1 Semino mal o m: b ounds on he emainde
We s a wi h he Hamil onian (3), whe e he no mal owis educed o cons an co e-
cien s. Then, we p e o m a ni e numbe o (semi)no mal o m s eps, by using sui able
canonical ans o ma ions ha emo e he monomials (5) up o a ni e deg ee. This allows
o show he con e gence o he p o cess on he se
D
m
(

1
R
), whe e

1
is indep enden
om
R
and
R
is small enough. By selec ing he o de up o which he semino mal o m
is done as a sui able unc ion o
R
, i is p ossible o ob ain a emainde o he semino mal
o m which is exp onen ially small wi h
R
.This is con ained in Theo em 1.
2.2.2 Ellip ic o i a e e y s icky
Nowle us assume ha he ini al o us has all he no mal di ec ions o ellip ic yp e. In
his case we can ake
G
=
R
2
m
, hewhole se o no mal di ec ions.
Then, using he no mal o m explained ab o e, one can w i e he ini ial Hamil onian
as an in eg able one plus an exp onen ially small p e u ba ion. Hence, i is e y na u al
o ob ain exp onen ially big es ima es o he diusion ime: he ime needed o a eal
a jec o y o go away om he se
D
m
(
 R
) ( o a p ecise deni ion o going away" see
Theo em 2) is bigge han
T
(
R
)=
cons :
exp
0
@
cons :

1
R

2

+1
1
A

(8)
b eing he cons an s on he deni ion o
T
(
R
) indep enden om
R
.As usual, we call he
exp onen
2

+1
he s abili y exp onen .
Le us compa e his esul wi h p e ious ones. In he case in which he ini ial o us is o
maximal dimension, no e ha he no mal a iables
z
>
=(
x
>
y
>
) a e missing e e ywhe e.
So, he se
D
m
(
 R
) (see (1)) eads
D
`
0
(
 R
)=
(
^

^
I
)
2
C
`

C
`
:
j
Im
^

j
 
j
^
I
j
R
2
g
:
To compa e wi h 13] we mus edene
R
2
as
R
,in o de o ha e he same uni s. Then,
he s abili y exp onen in (8) coincides wi h 13].
I he ini ial o us is an equilib ium p oin , he a iables
^

and
^
I
a e he ones ha a e
missing. Hence,
D
m
(
 R
) b ecomes
D
0
`
(0
R
)=
(
x y
)
2
C
`

C
`
:
j
(
x y
)
j
R
g
:
Hence, no escaling is necessa y o compa e he diusion ime o (8) wi h he one de i ed
om 6]: he imp o emen is ha he exp onen
1

+1
in 6] he e b ecomes
2

+1
. We no e
ha his imp o emen is no only on he diusion ime, bu also on he measu e o he
des oyed o i (see Rema k 10).
A. Jo ba and J. Villanue a
9
2.2.3 Can o amilies o in a ian o i
I is clea om Sec ion 2.1.3 ha compu ing he semino mal o mal o m asso cia ed o
G
a ound he ini ial o us, up o ni e o de , and skipping he non-in eg able emainde ,
hose ellip ic di ec ions dene a unique (
+
m
1
)-dimensional amily o (
+
m
1
)-dimensional
o i a ound he ini ial
-dimensional one. When we app oach he ini al o us, he in insic
equencies o he o i o he amily can b e selec ed such ha hey end o
!
(0)
.
In his case we will show ha when we add he emainde o he semino mal o m
mos o hese o i s ill p e sis in he comple e sys em
H
,ha ing also educible no mal
ow. The no mal eigen alues o hese o i a e close o he eigen alues
^

j
( ha a e he
ones no ela ed wi h
G
). O cou se, due o he die en small di iso s in ol ed in he
p oblem, we can no p o e he p e sis ence o all he in a ian o i p edic ed by he no mal
o m.
The hyp o heses needed a e usual in KAM me ho ds. The  s one is a non- esonance
condi ion in ol ing he equencies ^
!
(0)
and he no mal ones

, ha dep ends on he
conc e e selec ion o
G
and i is explici ly gi en in (4). The second hyp o hesis is a
nondegene acy condi ion, asking ha all he equencies a y wi h he ac ions. No e
ha , in gene al, we ha e mo e equencies (
+
m
) han ac ions (
+
m
1
,
m
1

m
). This
in o duces he classical lack-o -pa ame e s p oblem when wo king wi h lowe dimensional
o us, ha needs a sp ecial ea emen ( o ela ed esul s, see 4], 16] and 11]). The idea
ha weha e used he e is o cho ose a sui able (
+
m
1
)-dimensional se o pa ame e s, and
o ask o he exis ence o lowe dimensional o i asso cia ed o some o he alues o hese
pa ame e s. He e, he na u al pa ame e is he ec o o in insic equencies
!
2
R
+
m
1
o
he in a ian o i. To use his pa ame iza ion we need a ypical nondegene acy condi ion
on he equency map om
I
o
!
, his is, ha his map be a (lo cal) dieomo phism
a ound
I
= 0. This condi ion can be explici ly o mula ed compu ing he no mal o m
o Sec ion 2.1.3 up o deg ee 4 and i is gi en in (50). The con ol o he emaining
m
;
m
1
no mal equencies (no mal o he (
+
m
1
)-dimensional amily o o i) is mo e
dicul , since he e a e no ee pa ame e s o con ol hem. No e ha hose equencies
a e unc ions o he in insic ones. Then, he idea is o elimina e all he equencies o
which he Diophan ine condi ions needed o cons uc in a ian o i a e no sa ised.
This will lead us o elimina e alues o
!
o: a) con ol he in insic equencies
!
and b)
con ol he no mal ones as a unc ion o he in insic ones. Tocon ol he measu e o he
se o in isic equencies o which he asso cia ed no mal ones a e close o esonance, we
use he same kind o me ho d o 11]: we ask o a ex a se o nondegene acy condi ions
o he dep endence o hese no mal equencies wi h esp ec o he in insic ones. Those
condi ions a e gi en in (54). They ha e al eady b een conside ed in 12] and 7].
Wi h he o mula ion gi en ab o e, he esul is ha he measu e o he complemen a y
o he p ese ed o i is exp onen ially small: we in o duce
U
(
A
)=
n
!
2
R
+
m
1
:
j
!
;
!
(0)
j
A
o
A>
0

(9)
and le us dene
A
(
A
) as he se o equencies o
U
(
A
) o which we ha e educible
in a ian o i. Then, i
A
is small enough, we ha e
mes(
U
(
A
)
nA
(
A
))
mes(
U
(
A
))

cons :
exp
0
@
;
cons :

1
A

1

+1
1
A

16
No mal Beha iou o Lowe Dimensional To i
Then, he e exis s a cons an
$
, depending only on
,
m
,

,

0
,
^
N
4
,
^
N

,
^
S

,
^
T
3
and
^
T

,such ha he ol lowing bounds hold o he ans o med Hamil onian
H

!
G
1
,
j
N
(1)
;
N
j

4
R
4

$
^
S

R
p
+1


+2
+
R
2
p
;
1

2(

+2)
!

j
S
(1)
1
j

4
R
4

$
^
SR
p
+1

R
2


+1
+
R
4


+2
+
R
p
;
3


+2
+
R
p
;
2

2(

+2)
!

j
S
(1)
2
j

4
R
4

$
^
SR
p

R
2


+1
+
R
3


+2
+
R
p
;
1

2(

+2)
!

j
T
(1)
;
T
j

4
R
4

$
^
S

R
p
+1


+2
+
R
2
p
;
1

2(

+2)
!
:
Rema k 4
(A e y impo an one) I
p
is big enough and
 > R
, he dominan e m
in he bounds o
S
(1)
1
and
S
(1)
2
is gi en by he ac o
R
2
=

+1
. This wil l be he ac o o
dec easing o hose e ms du ing he no mal o m p ocess and i al lows o ake

o o de
R
2
=
(

+1)
, ha wil l p oduce he exponen
2
=
(

+1)
in
(36)
.As we ha e
2
=
(

+1)
<
1
, we
can deduce ha an adequa e selec ion o
p
is
p
=8
.This al lows o keep bounds like
(35)
du ing al l he i e a i e p ocess.
I we s a wi h a aw" Hamil onian (wi hou any p e ious s ep o no mal o m) he
dec easing ac o ob ained is o o de
R=

+1
, ha o ces us o selec

o o de
R
1
=
(

+1)
.
This p oduces a wo se exponen
1
=
(

+1)
in
(36)
. Fo ins ance, le us assume ha he
no mal o m has been done a ound an el lip ic equilib ium poin . He e he impo an issue
is o no e ha he bounds ob ained when kil ling deg ee
3
a e much wo se han he bounds
ob ained o he o he deg ees ( his has been obse ed nume ical ly in
17]
). Hence, o apply
he same bounds o al l he deg ees esul s in poo es ima es.
Rema k 5
The exponen
2
=
(

+1)
in Rema k
4
can be imp o ed in some e y degene a e
cases. Fo ins ance, le us conside a o al ly el lip ic o us, and we ake
G
=
R
2
m
. Le
q
be he lowes deg ee o he monomials o
N
co esponding o he ( o mal) no mal o m o
H
a ound he o us (o cou se,
q

4
). Then,

can be aken o o de
R
(
q
;
2)
=
(

+1)
, ha
p oduces he exponen
(
q
;
2)
=
(

+1)
in
(36)
.
P o o :
Du ing his p o o we will use die en cons an s $
j
,
j

0, ha will dep end only
on he same pa ame e s as he nal cons an $ o he s a emen o he lemma. Fi s ,
om he b ound (24) o Lemma 1, we ha e ha
j
G
1
j

1
R
1

$
0
^
SR
p
+1



j
G
2
j

1
R
1

$
0
^
SR
p



j
G
j

1
R
1

$
0
^
SR
p



whe e, as in Lemma 1,

j
=

;
j
and
R
j
=
R
exp (
;
j
). Then, o ob ain he b ounds o
he die en e ms o he ans o med Hamil onian, we only need o b ound he Poisson
b acke s ha app ea in (29){(33).
To ob ain p ecise es ima es, we will lo ok ca e ully in o he c i ical b ounds o he
die en pa ial de i a i es in ol ed, ha is, he ones asso cia ed o
N
4
and
T
3
. So, we
es ima e, sepa a ely, he con ibu ion o
N
4
,
N

,
T
3
and
T

, aking in o accoun ha
N
do es no dep end on
^

,
N
4
is a p olynomial o deg ee 4, and
T
3
only con ains e ms o
deg ee 3. Mo eo e , o b ound
e
S
2
(
T G
1
g
)we no e ha ( om he deni ion o
S
1
and
S
2
)

A. Jo ba and J. Villanue a
17
i only con ains e ms co esp onding o
@
@
^
Z
, and no o
@
@
^

o
@
@
^
I
.Thus, using he b ounds
on he Poisson b acke p o ided by Lemma 6 (see Rema k 11 o he case in which one
o he e ms has ni e deg ee), we ha e
j
e
S
2
(
T G
1
g
)
j

2
R
2

$
1
^
SR
p

R
2


+1
+
R
3


+2
!

j
T G
gj

2
R
2

$
2
^
S
R
p
+1


+2

j
N G
1
gj

2
R
2

$
3
^
SR
p
+1

R
2


+1
+
R
4


+2
!

j
N G
gj

2
R
2

$
4
^
SR
p

R
2


+1
+
R
4


+2
!

j
S G
gj

2
R
2

$
5
^
S
R
2
p
;
2


+2

j
T G
g
G
gj

3
R
3

$
6
^
S
R
2
p
;
1

2(

+2)

j
N G
g
G
gj

3
R
3

$
7
^
S

R
2
p

2

+3
+
R
2
p
+2

2(

+2)
!

and nally
j
H

j

4
R
4

$
8
^
S

R
2
p
;
2


+2
+
R
2
p
;
1

2(

+2)
!
:
F om ha , wi h a sui able deni ion o $ as a unc ion o $
0
{$
8
, he b ounds o he
s a emen o he lemma a e clea , i we ecall ha we ha e aken
p

6.
Now, we a e in condi ions o o mula e a quan i a i e esul ab ou pa ial educ ion
o semino mal o m" o he ini ial Hamil onian. Fo his pu p ose, we conside he Hamil-
onian
H
o (3), w i en as in (17) in e ms o he
Z
a iables. We assume ha
H
is
dened on
D
m
(

0
R
0
), o some 0
<
0
<
1 and 0
<R
0
<
1, wi h he ollowing b ounds:
j
N
j

0
R

^
NR
4
,
j
S
j

0
R

^
SR
3
and
j
T
j

0
R

^
TR
3
, o any 0
< R

R
0
, b eing
^
N
,
^
S
and
^
T
, p osi i e cons an s (indep enden om
R
). Then, we p o e he ollowing esul :
Theo em 1
We conside he Hamil onian
H
o
(17)
,wi h he hypo heses p e iously de-
sc ibed. We suppose ha he e exis s

0
>
0
and
>
+
m
1
such ha
j
ik
>
^
!
(0)
+
l
>

j

0
(
j
k
j
1
+
j
l
x
;
l
y
j
1
)

8
(
l s
)
2S 8
k
2
Z
wi h
j
l
x
;
l
y
j
1
+
j
k
j
1
6
=0
:
Then, o any
R>
0
smal l enough ( his condi ion on
R
depends only on
,
m
,

,

0
,

0
,
R
0
,
^
N
,
^
S
and
^
T
), he e exis s an analy ical canonical ans o ma ion
!
R
such ha
1.
!
R
;
Id
and
(!
R
)
;
1
;
Id
a e
2

-pe iodic on
^

.
2.
!
R
:
D
m
(3

0
=
4
R
exp (
;

0
=
4))
;!D
m
(

0
R
)

and
(!
R
)
;
1
:
D
m
(11

0
=
16
R
exp (
;
5

0
=
16))
;!D
m
(

0
R
)
:
18
No mal Beha iou o Lowe Dimensional To i
3. I we ake
(
^
 X
^
I Y
)
2D
m
(3

0
=
4
R
exp (
;

0
=
4))
and we dene
(
^


X


^
I

Y

)=
!
R
(
^
 X
^
I Y
)
, hen
j
^


;
^

j 

0
=
16
,
j
Z

;
Z
j 
R
0
exp (
;
1
=
2)
=
32
,
j
^
I

;
^
I
j 
R
2

0
exp (
;
1)
=
16
.Mo eo e , he same bounds hold o
(!
R
)
;
1
i
(
^
 X
^
I Y
)
2
D
m
(11

0
=
16
R
exp (
;
5

0
=
16))
.
4.
!
R
ans o ms
H
R
:=
H

!
R
= ^
!
(0)
>
^
I
+
1
2
Z
>
B

Z
+
N
R
+
S
R
+
T
R

decomposi ion analogous o
(17)
,wi h he bounds:
j
N
R
;
N
4
j
3

0
=
4
R
exp (
;

0
=
4)

cons :R
6
,
j
T
R
;
T
3
j
3

0
=
4
R
exp (
;

0
=
4)

cons :R
4
, whe e
N
4
and
T
3
we e in oducedin
(34)
, and can becompu ed wi h a no mal o m wi h espec o
S
up o deg ee
4
,and
j
S
R
j
3

0
=
4
R
exp (
;

0
=
4)

cons :
exp
0
@
;
cons :

1
R

2

+1
1
A
R
8

(36)
being he cons a s ha appea in he bounds o
N
R
,
T
R
and
S
R
, posi i e and inde-
penden om
R
.Mo eo e , o any
R
o which he esul holds,
H
R
is in no mal
o m wi h espec o
S
, a leas up o deg ee
8
.
Rema k 6
The dependence o
!
R
on
R
is no con inuous bu piecewise analy ic.
Rema k 7
F om he bounds p o idedbyLemma
2
o he i e a i e no mal o m p ocedu e
desc ibed in Lemma
1
, his exponen ial ly smal l bound seems o be he bes ha one can
ob ains by using his linea ly con e gen scheme.
P o o :
The p o o is done simul aneously o any0
<R

R
0
. The b ounds whe e
R
is no
w i en explici ly a e indep enden om
R
. All hese bounds and he die en condi ions
on he smallness o
R
will dep end only on he xed pa ame e s o he s a emen . The
main idea o his p o o is o use Lemma 1 ecu si ely,and o i e a e he b ounds p o ided
by Lemma 2 o
p
= 8 (see Rema k 4). Hence, o use his lemma, we need o pu he
ini ial Hamil onian in no mal o m wi h esp ec o
S
,up o deg ee a leas 8. Fo his
pu p ose, we cons uc ecu si ely he gene a ing unc ions
G
(0)
,
G
(1)
,
:::
,
G
(5)
,p o ided
by Lemma 1. Pu ing
H
(0)
=
H
, we can dene
H
(
n
+1)
:=
H
(
n
)

!
G
(
n
)
1
=
H
(
n
)
+
H
(
n
)
G
(
n
)
g
+
1
2!
H
(
n
)
G
(
n
)
g
G
(
n
)
g
+


(37)
o
n
= 0
:::
5. Le us conside  s he exp ession (37) as a o mal ans o ma ion.
F om he p op e y (14) o he Poisson b acke , and om he way in which he die en
G
(
j
)
a e selec ed in Lemma 1 (see Rema k 2), we can ensu e ha he non- esonan e ms
asso cia ed o
S
ha emain in
H
(6)
a e o deg ee a leas 9. Toshow ha his cons uc ion
is no only o mal, we a e going o p o e hewell dened cha ac e o he ans o ma ions
!
G
(
n
)
1
,
n
=0
:::
5, and o b ound
H
(
n
)
,
n
=1
:::
6. Fo his pu p ose, we expand
H
(
n
)
as
in (17), bu adding he sup e sc ip (
n
)" o
N
,
S
and
T
. We dene

0
=

0
192
, oin o duce

(0)
=

0
,
R
(0)
=
R
, and

(
n
)
=

(
n
;
1)
;
4

0
,
R
(
n
)
=
R
(
n
;
1)
exp (
;
4

0
),
n
=1
:::
6. Then,
we a e going o show ha aking



0
in Lemma 1, we ha e o
n
=0
:::
6, ha , i
R
is small enough,
j
N
(
n
)
j

(
n
)
R
(
n
)

^
N
(
n
)
(
R
(
n
)
)
4

j
S
(
n
)
j

(
n
)
R
(
n
)

^
S
(
n
)
(
R
(
n
)
)
n
+3

j
T
(
n
)
j

(
n
)
R
(
n
)

^
T
(
n
)
(
R
(
n
)
)
3
:
(38)
A. Jo ba and J. Villanue a
19
This is p o ed by (ni e) induc ion: assuming ha (38) holds o some
n
(0

n

5) and
using ha , i
R
is sucien ly small,
"
^
S
(
n
)
(
R
(
n
)
)
n
+1


+2
0

1 (39)
(" is p o ided by Lemma 1), we ha e
!
G
(
n
)
1

!
G
(
n
)
;
1
:
D
m
(

(
n
+1)
R
(
n
+1)
)
;!D
m
(

(
n
)
;
3

0
R
(
n
)
exp (
;
3

0
))
:
(40)
Then, he ac ha he successi e s eps inc ease a leas by one he deg ee o he no mal
o m wi h esp ec o
S
, makes e iden he es ima es o (38) o
n
+1. Fo mo e de ails
one can ew i e, wi h mino changes, he p o o o Lemma 2, using (38) ins ead o (35).
He e, he die en
R
-indep enden cons an s
^
N
(
n
)
,
^
T
(
n
)
and
^
S
(
n
)
,dened ecu si ely o
n
= 0
:::
6, dep end only on he same pa ame e s in ol ed in he o mula ion o he
Theo em. We ema k ha condi ion (39) o
n
=0
:::
5, imp oses only ani e numbe
o es ic ions on
R
.Le
R

0
he bigges alue o
R
o which hey hold.
The nex s ep is o con inue wi h he i e a i e no mal o m p o cess, bu using Lemma 2
(wi h
p
= 8) o bound
H
(
n
)
, 6

n

L
+1 (
L
will be de e mined b elow). This will be
done in an induc i eway,showing ha b ounds like (35) hold o each
H
(
n
)
,
n

6. Hence,
we add in (35) he sup e sc ip (
n
)" o
S
,
S
1
,
S
2
,
N

and
T

,andwe eplace
^
S
,
^
N

and
^
T

by
^
S
(
n
)
,
^
N
(
n
)

and
^
T
(
n
)

. All hese b ounds ha e b een aken on
D
m
(

(
n
)
R
(
n
)
), o some

(
n
)
,
R
(
n
)
ha will be de e mined below. Ini ially, o
n
=6, we can ake o ins ance
^
N
(6)
4
=
^
N
(6)
and
^
N
(6)

=
^
N
(6)
=
(
R

0
)
2
. The deni ion o he o he sup e -(6) cons an s
can be done simila ly. Be o e con inuing he i e a i e p o cedu e, we ema k ha , as he
ollowing s eps only a ec high o de e ms,
N
4
and
T
3
emain in a ian du ing all he
no mal o m p o cedu e. Then, Rema k 4 sugges s he deni ion



(
R
)=(
AR
)
2
=
(

+1)
,
whe e
A

1 will be de e mined la e (indep enden ly om
R
). F om his alue o

we
dene, ecu si ely,

(
n
+1)
=

(
n
)
;
4

,
R
(
n
+1)
=
R
(
n
)
exp (
;
4

), o
n

6. To p ese e he
p osi i eness o

(
n
)
, we es ic
n

L
(
R
), being
L
(
R
) he g ea es in ege o which we
ha e 4(
L
;
5)



0
=
8. This implies he ollowing es ic ion on
L
:
L

5+

0
32

1
AR

2

+1
:
(41)
Hence, we ake as
L
he in ege pa o (41). This implies
R
exp (
;

0
=
4)

R
(
n
)

R
i
6

n

L
+1. To apply Lemma 2, we assume ha o he cu en Hamil onian
H
(
n
)
,
6

n

L
, we ha e
^
S
(
n
)

^
S
(6)
,
^
N
(
n
)


^
N

and
^
T
(
n
)


^
T

, o some
^
N

and
^
T

o
b e p ecised la e ( hose b ounds a e necessa y o dene $ in Lemma 2, indep enden om
n
). I o he cu en alue o
n
we ha e
"
^
S
(
n
)
(
R
(
n
)
)
6


+2

1

(42)
hen, he canonical ans o ma ion !
G
(
n
)
1
gi en by Lemma 1 ac s like (40), eplacing

0
by

. The e o e, using Lemma 2, and ecalling ha
2

+1
<
1,
A

1and
R
(
n
)
< R <
1,
one ob ains he ollowing b ounds o he ans o med Hamil onian:
j
N
(
n
+1)
;
N
(
n
)
j

(
n
+1)
R
(
n
+1)

$
^
S
(
n
)

(
R
(
n
)
)
9
A
2
R
2
+
(
R
(
n
)
)
15

2
A
4
R
4
!

2$
^
S
(
n
)
A
2
(
R
(
n
)
)
6

20
No mal Beha iou o Lowe Dimensional To i
j
S
(
n
+1)
1
j

(
n
+1)
R
(
n
+1)

$
^
S
(
n
)
(
R
(
n
)
)
9

(
R
(
n
)
)
2
A
2
R
2
+
(
R
(
n
)
)
4
A
2
R
2
+
(
R
(
n
)
)
5
A
2
R
2
+
(
R
(
n
)
)
6

2
A
4
R
4
!


4$
^
S
(
n
)
A
2
(
R
(
n
)
)
9

j
S
(
n
+1)
2
j

(
n
+1)
R
(
n
+1)

$
^
S
(
n
)
(
R
(
n
)
)
8

(
R
(
n
)
)
2
A
2
R
2
+
(
R
(
n
)
)
3
A
2
R
2
+
(
R
(
n
)
)
7

2
A
4
R
4
!

3$
^
S
(
n
)
A
2
(
R
(
n
)
)
8

j
T
(
n
+1)
;
T
(
n
)
j

(
n
+1)
R
(
n
+1)

$
^
S
(
n
)

(
R
(
n
)
)
9
A
2
R
2
+
(
R
(
n
)
)
15

2
A
4
R
4
!

2$
^
S
(
n
)
A
2
(
R
(
n
)
)
4
:
We ake
A
= max
n
1

q
8$ exp (1)
o
,and hen, ecalling ha
R
(
n
+1)
=
R
(
n
)
exp (
;
4

), we
can dene induc i ely (
n

6),
^
S
(
n
+1)
=
(exp (4

))
9
exp (1)
^
S
(
n
)

^
N
(
n
+1)

=(exp (4

))
9

^
N
(
n
)

+
1
exp (1)
^
S
(
n
)
!

^
T
(
n
+1)

=(exp (4

))
9

^
T
(
n
)

+
1
exp (1)
^
S
(
n
)
!
:
Assuming
R
small enough such ha


1
=
72, we ob ain
^
S
(
n
)
=
^
S
(6)
exp ((6
;
n
)(1
;
36

))

^
S
(6)
exp ((6
;
n
)
=
2)

(43)
^
N
(
n
)


exp (36

(
n
;
6))

^
N
(6)

+
^
S
(6)
1
(exp (1)
;
1)
!

^
T
(
n
)


exp (36

(
n
;
6))

^
T
(6)

+
^
S
(6)
1
(exp (1)
;
1)
!
:
As we a e only in e es ed in hose b ounds o
n

L
+ 1, om he es ic ion on
L
in (41)
we can easily in o duce
n
-indep enden bounds
^
N

and
^
T

o
^
N
(
n
)

and
^
T
(
n
)

. Now,
assuming ha all he s eps a e well dened, i one pu s
n

L
(
R
) + 1 in (43), we ob ain he
exp onen ially small b ound o he s a emen o
^
S
(
L
+1)
. To jus i y ha we can each his
alue, we no e ha (42) holds o all he p e ious
n
,i we es ic
R
wi h "
^
S
(6)
R
3

1.
Then, o p o e he Theo em, we only ha e o in o duce !
R
= !
G
(0)
1

:::

!
G
(
L
)
1
,
and hence, (!
R
)
;
1
= !
G
(
L
)
;
1

:::

!
G
(0)
;
1
.I hose ans o ma ions ac as i has b een
said in he s a emen , he p o o is nished. Fi s , and om he domains o deni ion o
he die en canonical ans o ma ions !
G
(
n
)
1
(see (40), eplacing

0
by

i
n

6), we
deduce ha !
R
is dened on he domain gi en in he s a emen . Mo eo e , om he
b ounds o he die en componen s o !
G
(
n
)
1
;
Id
gi en by Lemma 1, and ema king ha
6

0
+(
L
;
5)



0
=
16, he nal bounds o !
R
;
Id
ollow immedia ly. We conside
now(!
R
)
;
1
. In his case, and using he same a gumen s on !
G
(
n
)
;
1
,one can check ha
i we dene

n
=11

0
=
16 +
n
0
,
R
n
=
R
exp (
;
5

0
=
16 +
n
0
) o
n
= 0
:::
6, and

n
=11

0
=
16 + 6

0
+(
n
;
6)

,
R
n
=
R
exp (
;
5

0
=
16 + 6

0
+(
n
;
6)

) o
n
=6
:::L
+1,
hen we ha e
!
G
(
n
)
;
1
:
D
m
(

n
R
n
)
;!D
m
(

n
+1
R
n
+1
)

o 0

n

L
. The p o o o his ac can b e done by combining he b ounds on !
G
(
n
)
;
1
;
Id
wi h he inequali y (27). Mo eo e , his allows o es ima e (!
R
)
;
1
;
Id
as i has b een
done wi h he case o !
R
.
A. Jo ba and J. Villanue a
21
3.3 Eec i e s abili y
An immedia e consequence o Theo em 1 is ha we can b ound he diusion sp eed a ound
a linea ly s able o us o a Hamil onian sys em. In his case, we ake
G
=
R
2
m
, and
hence,
S
=
N
. Then, we apply Theo em 1, wi hou aking in o accoun he e m
T
o
he decomp osi ion (17). In ac , in his case one can ew i e he p o o s o Lemmas 1,
2, and Theo em 1, in a simple o m (al hough he ac ual o mula ion also holds in his
pa icula case), o ob ain exp onen ially small b ounds o he emainde
S
R
.
Theo em 2
We conside he eal analy ic Hamil onian
(3)
dened on
D
m
(

0
R
0
)
o
some
0
< 
0
<
1
and
R
0
>
0
. We also assume ha al l he eigen alues o
J
m
B
a e o
el lip ic ype, and ha he e exis s

0
>
0
and
>`
such ha
j
ik
>
^
!
(0)
+
l
>

j

0
(
j
k
j
1
+
j
l
x
;
l
y
j
1
)

8
l
2
N
2
m
8
k
2
Z
wi h
j
l
x
;
l
y
j
1
+
j
k
j
1
6
=0
:
Le
R
2
(0
R
0
)
, and le us ake eal ini ial condi ions a
= 0
con ained in
D
m
(0
R
)
.
Then, we can dene
>
2
such ha , i
R
is smal l enough, he co esponding ajec o ies
belong o
D
m
(0
R
)
o any ime
0


T
(
R
)
,wi h
T
(
R
)=
cons :
exp
0
@
cons :

1
R

2

+1
1
A

being he cons an s in he deni ion o
T
(
R
)
independen om
R
.
Rema k 8
In he p oo , and only o echnical easons,

depends on

0
. Ne e heless,
we can ake

as close as we wan o
2
(by aking an ini ial

0
smal l enough, see he p oo
o de ails), bu his implies a educ ion on he se o al lowed
R
, and on he cons an s o
he s abili y ime.
The eason ha o ces o ake
>
2
is he no m used o he no mal a iables. I one
akes he Euclidean no m ins ead o he sup emum no m, he condi ion
>
2
is eplaced
by
>
1
.
P o o :
In o de o simpli y he p o o , we assume ha he ini ial eal a iables (
x y
) o
(3) co esp ond o he ones ha pu
B
in canonical eal o m, ha is,
z
>
B
z
=
m
X
j
=1

j
(
x
2
j
+
y
2
j
)

wi h

j
=
i
j
,
j
=1
:::m
.Mo eo e , we assume ha
R
0
<
1. We in o duce (
X Y
) o
deno e he complexied a iables
x
j
=
X
j
+
iY
j
p
2
 y
j
=
iX
j
+
Y
j
p
2
 j
=1
:::m
(44)
ha pu he ma ix
J
m
B
in he diagonal o m
J
m
B

.Then, we can w i e he Hamil onian
in hese a iables as
H
= ^
!
(0)
>
^
I
+
1
2
Z
>
B

Z
+
N
(
X
^
I Y
)+
S
(
^
 X
^
I Y
)


22
No mal Beha iou o Lowe Dimensional To i
whe e
N
can b e ew i en as a unc ion o
I
,
I
>
=(
^
I
>

~
I
>
), wi h
~
I
j
=
iX
j
Y
j
=
1
2
(
x
2
j
+
y
2
j
),
and
S
e ies
N
(
S
)=0. This co esp onds o he decomp osi ion (17) i one pu s
S
=
N
.
H
is dened on
D
m
(

0
R
0
=
p
2), wi h bounds o he ollowing o m:
j
N
j

0
R

^
NR
4
and
j
S
j

0
R

^
SR
3
, o any 0
< R

R
0
=
p
2. Now, we apply Theo em 1 and we ob ain,
o any
R
small enough, a canonical change !
R
such ha in he new co o dina e sys em
(
^
 X
^
I Y
)=!
R
(
^

R
X
R

^
I
R
Y
R
), we ha e
H
R
:=
H
!
R
= ^
!
(0)
>
^
I
R
+
1
2
(
Z
R
)
>
B

Z
R
+
N
R
(
X
R

^
I
R
Y
R
)+
S
R
(
^

R
X
R

^
I
R
Y
R
)

b eing
N
R
a unc ion o (
I
R
)
>
= ((
^
I
R
)
>

(
~
I
R
)
>
), wi h
~
I
R
j
=
iX
R
j
Y
R
j
.
H
R
is dened on
D
m
(3

0
=
4
R
exp (
;

0
=
4)), wi h
j
S
R
j
3

0
=
4
R
exp (
;

0
=
4)

cons :
exp
0
@
;
cons :

1
R

2

+1
1
A
R
8
:=
M
(
R
)
:
The canonical equa ions o (
X
R

^
I
R
Y
R
)a e
_
X
R
j
=
@
H
R
@Y
R
j

_
Y
R
j
=
;
@
H
R
@X
R
j
 j
=1
:::m
_
I
R
j
=
@
H
R
@
^

R
j
=
@S
R
@
^

R
j
 j
=1
::: :
(45)
F om his, one ob ains (using ha
N
R
is in ac only a unc ion o
I
, and ecalling
`
=
+
m
),
_
I
R
j
=
i
@
H
R
@Y
R
j
Y
R
j
;
i
@
H
R
@X
R
j
X
R
j
=
i
@S
R
@Y
R
j
Y
R
j
;
i
@S
R
@X
R
j
X
R
j
 j
=
+1
:::`:
Wepu
I
R
j
(
^

R
X
R

^
I
R
Y
R
) o he exp essions on he igh -hand side o
_
I
R
j
,
j
=1
:::`
.
We use Lemma 5 o b ound hese exp essions. Then, o
j
=1
:::
one has
jI
R
j
j
0
R
exp (
;

0
=
2)

4
M
(
R
)
3

0
exp (1)
:
(46)
I we combine Lemma 5 wi h he inequali y (27), one ob ains o
j
=
+1
:::`
ha ,
jI
R
j
j
0
R
exp (
;

0
=
2)

2
M
(
R
) exp (
;

0
=
2)
exp (
;

0
=
4)(1
;
exp (
;

0
=
4))

16
M
(
R
) exp (
;

0
=
4)

0
:
(47)
Tocon inue he p o o , we pu (
x
R
y
R
) o he a iables ha come om he ealica ion"
o (
X
R
Y
R
), ha is,
X
R
j
=(
x
R
j
;
iy
R
j
)
=
p
2,
Y
R
j
=(
y
R
j
;
ix
R
j
)
=
p
2. In ac , as !
R
p ese es
he symme ies o
H
(due o he complexica ion o a eal Hamil onian, see Sec ion 2.1.2),
weha e ha he Hamil onian in he a iables (
x
R
y
R
) is eal analy ic. Towo k wi h hose
die en ep esen a ions o he a iables, we gi e he ollowing ema ks: (
i
) he se o eal
a iables (
x
j
y
j
)such ha
j
x
j
j

j
y
j
j
A
is con ained in he se o complex (
X
j
Y
j
) such
ha
j
X
j
j

j
Y
j
j
A
, (
ii
) he se o complex (
X
j
Y
j
)such ha
j
X
j
j

j
Y
j
j
A
, is con ained
in he complex se o (
x
j
y
j
) such ha
j
x
j
j

j
y
j
j
p
2
A
( his p op e y has been used o
say ha
H
is dened in
D
m
(

0
R
0
=
p
2)), (
iii
) he se o eal (
x
j
y
j
) such ha
I
j

A
2
,
A. Jo ba and J. Villanue a
23
is con ained in he se o eal (
x
j
y
j
)such ha
j
x
j
j

j
y
j
j
p
2
A
. Those ema ks a e used
when wo king wi h hese die en kind o a iables, and one wan s o con ol he size o
he co esp onding domains, when we change he a iable ep esen a ion.
Now, we ake eal alues o (
^

R
x
R

^
I
R
y
R
) as ini ial condi ions a
= 0. To p o e
he lowe bound o he s abili y ime, we conside a xed 0
<  <
1, and we es ic
o ini ial condi ions such ha , when exp essed in e ms o (
^

R
X
R

^
I
R
Y
R
), hey b elong
o
D
m
(0
R
exp (
;

0
=
2)
=
p
2). Then, we ha e ha he co esp onding ini ial ac ions
I
R
a e b ounded by
j
I
R
j
(0)
j 
R
2

2
exp (
;

0
)
=
2,
j
= 1
:::`
. Using his, we deduce om
he b ounds (46) and (47) ha , o he a jec o ies o he Hamil onian equa ions (45), we
ha e
j
I
R
j
(
)
j
R
2
exp (
;

0
)
=
2 o 0


T
(
R
), whe e we can ake
T
(
R
)=
R
2

0
exp (
;
3

0
=
4)(1
;

2
)
32
M
(
R
)
:
This bound comes om (47), ha is he wo s case. This is he exp ession o he
s abili y ime o he s a emen o he Theo em. To use he bounds (46) and (47) o
I
R
j
, we need ha hese a jec o ies exp essed in e ms o (
^

R
X
R

^
I
R
Y
R
) b elong o
D
m
(0
R
exp (
;

0
=
2)) up o ime
T
(
R
). As we ha e
j
I
R
j
(
)
j 
R
2
exp (
;

0
)
=
2, his
ollows om ema ks (
iii
) and (
i
). F om ha we deduce, using he b ounds o (!
R
)
;
1
;
Id
p o ided by Theo em 1 and ema k (
ii
), ha he co esp onding eal a jec o ies in e ms
o (
^
 x
^
I y
) a e con ained in
D
m
(0
R
1
), being
R
1
dened by
R
1
=max
8
<
:
p
2

R
exp

;

0
2

+
R
0
exp (
;
1
=
2)
32
!

s
R
2
exp (
;

0
)+
R
2

0
exp (
;
1)
16
9
=

:
Then, i we gi e o (
^
 x
^
I y
) a eal se o poin s such ha , exp essed in e ms o
(
^
 X
^
I Y
), hey b elong o he domain (!
R
)
;
1
(
D
m
(0
R
exp (
;

0
=
2)
=
p
2)), hen, he
a jec o ies o
H
wi h ini ial condi ions in his se emain in
D
m
(0
R
1
) o a ime span
T
(
R
). Wi h simila a gumen s as he ones used o dene
R
1
(using now ema k (
ii
)), one
can check ha his domain can be aken as
D
m
(0
R
2
), b eing
R
2
dened by
R
2
=min
8
<
:
R
exp (
;

0
=
2)
p
2
;
R
0
exp (
;
1
=
2)
32

s
R
2

2
exp (
;

0
)
2
;
R
2

0
exp (
;
1)
16
9
=

:
I one conside s he ow !
H
dened om
D
m
(0
R
2
)
R
2
`
o
D
m
(0
R
1
)
R
2
`
, o
0


T
(
R
), hen, pu ing
R

R
2
in he s a emen , and aking an
R
-indep enden
alue o

close enough o1such ha
R
2
>
0, we can dene

=
R
1
=R
2
.
4 Es ima es on he amilies o lowe dimensional o i
Le us conside he eal analy ic educed Hamil onian
H
o (3) and a xed subbundle
G
o
ellip ic di ec ions o
J
m
B
. In Theo em 1 weha e p o ed ha , unde s anda d Diophan ine
condi ions, one can pu
H
in no mal o m wi h esp ec o he se
S
(see (15) and (16)
o he deni ion), wi h an exp onen ially small emainde . I we w i e his semino mal
o m in e ms o he complexied a iables
Z
,and wi hou changing he name o he
Hamil onian, one has
H
=
!
(0)
>
I
+
1
2
^
Z
>
^
B

^
Z
+
F
(
I
)+
1
2
^
Z
>
Q
(
I
)
^
Z
+
T
(
^
 X
^
I Y
)+
R
(
^
 X
^
I Y
)
:
(48)
24
No mal Beha iou o Lowe Dimensional To i
To explain he no a ion used, le us ecall ha he die en esonan e ms dep end only on
^
I
and on he p o duc s
X
j
Y
j
,
j
=1
:::m
, bu , om he s uc u e o
S
, no all he p ossible
combina ions o hose monomials akeplacein
M
(
S
). Then, wein o duce
I
>
=(
^
I
>

~
I
>
),
wi h
~
I
j
=
iX
j
Y
j
,
j
=1
:::m
1
,andwi h his deni ion (48) can b e desc ib ed as ollows:
he symme ic ma ix
^
B

is dened om
B

skipping he 2
m
1
eigen alues asso cia ed o
G
,
J
m
;
m
1
^
B

= diag(
^

).
F
and
Q
co esp ond o he no mal o m wi h esp ec o
S
,wi h
he expansion o
F
s a ing a second o de wi h esp ec o
I
,and wi h
Q
(0) =0. I is
no dicul o check ha by cho osing he a iables
~
Z
in sui able o m (as i has b een
done in he p o o o Theo em 2),
F
is eal analy ic. Mo eo e ,
Q
is a symme ic ma ix
such ha
J
m
;
m
1
Q
is diagonal,
T2M
(
NnS
)(so
T 
O
3
(
^
Z
)) and
R2
M
(
S
).
We assume ha his no mal o m has b een done o a gi en (and small enough)
R
,as
in he o mula ion o Theo em 1. We only conside he
R
-dep endence when we gi e he
bounds o he die en e ms o (48). To ob ain hese b ounds, le us dene

1
=3

0
=
4,
whe e we ecall ha

0
is he wid h o he s ip o anali ici y, wi h esp ec o
^

, o he
ini ial Hamil onian. Then, Theo em 1 implies ha , o any
R
small enough, we ha e
jF j
0
R

^
F
R
4

jF
3
j
0
R

^
F
3
R
6

jQj
0
R

^
Q
R
2

jQ
2
j
0
R

^
Q
2
R
4

jT j

1
R

^
T
R
3

jRj

1
R

cons :
exp

;
cons :

1
R

2

+1

R
8

(49)
To de i e hese bounds on
D
m
(0
R
), we ha e conside ed he unc ions ha dep end on
~
I
as unc ions o
~
Z
. He e, we ha e spli
F
=
F
2
+
F
3
and
Q
=
Q
1
+
Q
2
.
F
2
and he
comp onen s o
Q
1
a e p olynomials on
I
o deg ees 2 and 1 esp ec i ely.
F
3
and
Q
2
con ain
he emaining e ms. We no e ha he deni ion o
F
2
and
Q
1
do es no dep end on he
o de o he semino mal o m.
This semino mal o m has b een o mally explained in Sec ion 2.1.3, and we will use
he no a ion ela ed o (7) o ep esen he no mal o m o i.
The main pu p ose o his sec ion is o s udy he p e sis ence o hose o i when we add
he emainde
R
. We no e ha , as
jRj
is exp onen ially small wi h
R
,we can exp ec ha
he o i o (7) will su i e, excep he ones co esp onding o a se o pa ame e s (
I
(0)) o
exp onen ially small measu e wi h esp ec o
R
. We will show ha his asse ion holds,
assuming ce ain s anda d nondegene acy condi ions on his amily o o i, ha ha e b een
explained in Sec ion 2.2.3 (condi ions ha , as we will see, can b e checked by compu ing a
no mal o m up o deg ee 4, ha is, om
F
2
and
Q
1
). As i is a mo e na u al pa ame e ,
he esul s will b e o mula ed in e ms o equencies ins ead o ac ions.
4.1 Nondegene acy condi ions
Be o e he igo ous o mula ion o he esul s, le us gi e in explici o m hese nondegen-
e acy condi ions.
4.1.1 Nondegene acy o he in insic equencies
The  s one is a s anda d nondegene acy condi ion on he dep endence o he equencies
wi h esp ec o he ac ions: we equi e
de
C 6
=0

C
=
@
2
F
2
@I
2
(0)
:
(50)
A. Jo ba and J. Villanue a
25
This allows o pa ame ize he o i o he amily by hei ec o o in insic equencies
(ins ead o
I
(0)). O cou se, weha e o b e close enough o he ini ial
-dimensional o us.
This asse ion is jus ied by he ollowing lemma:
Lemma 3
Le us assume ha
de
C 6
=0
. Then, i
R
is smal l enough, he e exis s a eal
analy ic ec o ial unc ion
I
(
!
)
,dened on he se

!
2
C
+
m
1
:
j
!
;
!
(0)
j
1
8
(
jC
;
1
j
)
;
1
R
2


(51)
such ha
@
F
@I
(
I
(
!
)) =
!
;
!
(0)

wi h
I
(
!
(0)
)=0
. Mo eo e , we ha e
jI
(
!
)
j
1
4
R
2
o any
!
in he se
(51)
,and i
!
(1)
,
!
(2)
belong in
(51)
, hen
jI
(
!
(1)
)
;I
(
!
(2)
)
j
2
jC
;
1
jj
!
(1)
;
!
(2)
j
:
O cou se, we a e s il l using he no a ion o Sec ion
4
.
P o o :
We ha e
F
(
I
) =
1
2
I
>
C
I
+
F
3
. Then, we ake a xed
!
in he se (51), and we
wan o sol e he equa ion:
I
(
!
)=
C
;
1

!
;
!
(0)
;
@
F
3
@I
(
I
(
!
))
!
:
(52)
Pu ing he sup e sc ip s (
k
+ 1)" and (
k
)" o
I
(
!
) in (52), we can conside his exp es-
sion as an i e a i e p o cedu e, using
I
(0)
(
!
) = 0 as he seed. I we assume
jI
(
k
)
(
!
)
j
1
4
R
2
,
hen, using Cauchy inequali ies, we ha e o
R
small enough,
jI
(
k
+1)
(
!
)
j jC
;
1
j

1
8
(
jC
;
1
j
)
;
1
R
2
+
^
F
3
R
6
3
4
R
2
!

1
4
R
2

whe e we ha e used he b ounds o (49) o
F
3
, ema king ha
jF
3
j
0
R
is abound o he
sup emum no m o
F
3
(
I
) i
j
I
j 
R
2
. Mo eo e , o ensu e con e gence, we ema k ha
using he main alue heo em one has,
jI
(
k
+1)
(
!
)
;I
(
k
)
(
!
)
j
(
+
m
1
)
^
F
3
R
6

3
8

2
R
4
jI
(
k
)
(
!
)
;I
(
k
;
1)
(
!
)
j
1
2
jI
(
k
)
(
!
)
;I
(
k
;
1)
(
!
)
j

i
R
is small enough. Clea ly, he limi unc ion is analy ic wi h esp ec o
!
,and om
he eal analy ic cha ac e o
F
,
I
is in ac eal analy ic. Taking
!
(1)
,
!
(2)
in he se
(51), one has
I
(
!
(1)
)
;I
(
!
(2)
)=
C
;
1
(
!
(1)
;
!
(2)
)+
C
;
1

@
F
3
@I
(
I
(
!
(2)
))
;
@
F
3
@I
(
I
(
!
(1)
))
!

and wi h he same a gumen s p e iously used, we ob ain o
R
small enough
jI
(
!
(1)
)
;I
(
!
(2)
)
j
2
jC
;
1
jj
!
(1)
;
!
(2)
j
:
32
No mal Beha iou o Lowe Dimensional To i
4.3.2 The i e a i e scheme
Now, we can desc ib e he i e a i e p o cedu e used o cons uc in a ian (
+
m
1
)-
dimensional o i. This p o cess is gi en by a sequence o canonical changes o a iables,
cons uc ed as he ime one ow o a sui able gene a ing unc ion
S
!
.The changes a e
cons uc ed o kill he e ms ha obs uc s he exis ence o an in a ian educed o us
wi h ec o o basic equencies gi en by
!
. As usual ( o o e come he eec o he small
di iso s), he changes a e chosen o p o duce a quad a ically con e gen scheme, ins ead
o he linea one o Lemma 1.
Fi s , we desc ib e a gene ic s ep o his i e a i e p o cess. Fo his pu p ose, we expand
he Hamil onian
H
(0)
in he ollowing o m
H
(0)
=
a
(

)+
b
(

)
>
^
Z
+
c
(

)
>
I
+
1
2
^
Z
>
B
(

)
^
Z
+
I
>
E
(

)
^
Z
+
1
2
I
>
C
(

)
I
+)(

^
X I
^
Y
)

(67)
whe e we do no w i e explici ly he
!
-dep endence and whe e weha e skipp ed he sup e -
sc ip (0)" in he die en pa s o he Hamil onian. F om his expansion, wein o duce
he ollowing no a ions: 
H
(0)
]
(
^
Z
^
Z
)
=
B
, 
H
(0)
]
(
I
^
Z
)
=
E
and
<H
(0)
>
=
H
(0)
;
). F om
he bounds on he e ms o he decomp osi ion (60), we ha e ha ~
a
,
b
,
c
;
!
,
B
;
^
B
(0)

,
C
;C
(0)
and
E
a e all
O
(
^
H
(0)
). No e ha i we a e able o kill he e ms ~
a
,
b
and
c
;
!
,
we will ob ain an in a ian o us wi h in insic equency
!
.Ne e heless, as we wan o
ha e simple equa ions a e e y s ep o he i e a i escheme ( his is, linea equa ions wi h
cons an co ecien s), we a e o ced o kill some hing mo e. Then, we ask he nal o us
o ha e educible no mal ow gi en by a diagonal ma ix. This is, we wan ha he new
ma ix
B
e ies
B
=
J
m
;
m
1
(
B
) whe e, o a (2
s
)-dimensional ma ix
A
(

) dep ending
2

-p e io dically on

, we dene
J
s
(
A
)=
;
J
s
dp(
J
s
A
). He e, dp(
A
) deno es he diagonal
ma ix ob ained aking he diagonal en ies o
A
. Mo eo e , we ha e o elimina e
E
o
uncouple he neu al" and he no mal di ec ions o he o us up o  s o de . Thus,
o each s ep o he i e a i e p o cess, we use a canonical change o a iables, gi en by a
gene a ing unc ion o he o m
S
(

^
X I
^
Y
)=

>

+
d
(

)+
e
(

)
>
^
Z
+
(

)
>
I
+
1
2
^
Z
>
G
(

)
^
Z
+
I
>
F
(

)
^
Z
whe e

2
C
+
m
1
,
d
=0,
= 0 and
G
is a symme ic ma ix, wi h
J
m
;
m
1
(
G
)=0. The
ans o med Hamil onian is
H
(1)
=
H
(0)

!
S
1
. We expand
H
(1)
in he same way as
H
(0)
in (67), keeping he same name o he new a iables, bu adding he sup e sc ip (1)"
o
a
,
b
,
c
,
B
,
C
,
E
and ). Then, we ask ~
a
(1)
=0,
b
(1)
= 0,
c
(1)
;
!
= 0,
E
(1)
= 0 and
B
(1)
=
J
m
;
m
1
(
B
(1)
). We will show ha his can be achie ed up o  s o de in he size
o
^
H
(0)
. Fo his pu p ose, we w i e hose condi ions in e ms o he ini ial Hamil onian
and he gene a ing unc ion, and hen, we ob ain he ollowing equa ions:
(
eq
1
) ~
a
;
@d
@
!
=0,
(
eq
2
)
b
;
@e
@
!
+
^
B
(0)

J
m
;
m
1
e
=0,
(
eq
3
)
c
;
!
;
@
@
!
;C
(0)


+

@d
@

>

=0,
(
eq
4
)
B

;J
m
;
m
1
(
B

)
;
@G
@
!
+
^
B
(0)

J
m
;
m
1
G
;
GJ
m
;
m
1
^
B
(0)

=0,

A. Jo ba and J. Villanue a
33
(
eq
5
)
E

;
@F
@
!
;
FJ
m
;
m
1
^
B
(0)

=0,
b eing
B

=
B
;
2
4
@H
(0)

@I
0
@

+

@d
@
!
>
1
A
;
@H
(0)

@
^
Z
J
m
;
m
1
e
3
5
(
^
Z
^
Z
)

E

=
E
;C
(0)

@e
@
!
>
;
2
4
@H
(0)

@I
0
@

+

@d
@
!
>
1
A
;
@H
(0)

@
^
Z
J
m
;
m
1
e
3
5
(
I
^
Z
)
:
To sol e hose homological equa ions, we expand hem in Fou ie se ies and we equa e
he co esp onding co ecien s, ob aining he o mal solu ions. The nex s ep is o de i e
bounds on hose solu ions. As we will use hese bounds in i e a i e o m, we wan o
make clea which exp essions change om one s ep o ano he , and which ones can be
b ounded indep enden ly om he s ep. Fo his pu p ose, we ake xed p osi i e cons an s
m
, ^
m
, ~
m
,

2
,

1
, ^

, ~

dened as wice he co esp onding ini al alues
m
(0)
, ^
m
(0)
, ~
m
(0)
,

(0)
2
,

(0)
1
, ^

(0)
, ~

(0)
and a xed

1
, 0
< 
1
< 
(0)
1
.In wha ollows,
^
N
will deno e an
exp ession dep ending only on
m
, ^
m
,

1
,

2
, ^

, he die en dimensions
,
m
,
m
1
, plus

and

0
.
^
N
will be edened du ing he desc ip ion o he i e a i e scheme o mee a
ni e numbe o condi ions. The idea is o p e o m he bounds on he i e a i e scheme
pu ing he sup e sc ip (0)" on he e ms ha change a e e y i e a ion. Hence, we
w i e he b ounds on
^
H
(0)
as
k
^
H
(0)
k
E
(0)

(0)
R
(0)

M
(0)
and
L
E
(0)

(0)
R
(0)
^
H
(0)
g
L
(0)
, wi h
M
(0)
(
R
)

M
(
R
) and
L
(0)
(
R
)

(
M
(
R
))
1
;

. Hence, using Lemma 5,
k
a
;

(0)
k
E
(0)

(0)

M
(0)

k
E
k
E
(0)

(0)

2(
m
;
m
1
)
M
(0)
(
R
(0)
)
3

k
c
;
!
k
E
(0)

(0)

M
(0)
(
R
(0)
)
2

k
B
;
^
B
(0)

k
E
(0)

(0)

(2(
m
;
m
1
)+1)
M
(0)
(
R
(0)
)
2

k
b
k
E
(0)

(0)

M
(0)
R
(0)

k
C
;C
(0)
k
E
(0)

(0)

(2(
+
m
1
)+1)
M
(0)
(
R
(0)
)
4

k
)
k
E
(0)

(0)
R
(0)

^

(0)
+
M
(0)
:
(68)
Mo eo e , we can use Lemma 11 o deduce ha he same b ounds hold o hei Lipschi z
cons an s on
E
(0)
, eplacing
M
(0)
by
L
(0)
,and ^

(0)
by ~

(0)
. Then, o p o e he con e gence
o he expansion o
S
,we need some kind o con ol on he die en small di iso s in ol ed.
Fo his pu p ose, we es ic he pa ame e
!
o he subse
E
(1)
(
R
)
 E
(0)
(
R
) o which
he ollowing Diophan ine es ima es hold: we say ha
!
2E
(1)
, i
!
2E
(0)
,and
j
ik
>
!
+
l
>
^

(0)
(
!
)
j

(0)
(
R
)
j
k
j

1
 k
2
Z
+
m
1
n
0
g
 l
2
N
2(
m
;
m
1
)

0
<
j
l
j
1

2

(69)
o ce ain

(0)
>
0. We exp ec he measu e o
E
(0)
nE
(1)
o be o o de

(0)
and, hence,
as we wan o ha e exp onen ially small b ounds o his measu e, we ake

(0)

(
M
(0)
)

.
Then, we p o ceed o b ound he solu ions o he die en homological equa ions. Fo his
pu p ose, we use Lemma 4. Mo e p ecisely, we dene

(0)
=(
M
(0)
)

,and we ake

(0)
as
a alue o

o use he die en es ima es p o ided by his lemma. In o de o simpli y
he p o o s, we assume

(0)
;
N
(0)


0
=
4, whe e
N
2
N
will b e a xed in ege ha will
be de e mined be o e he desc ip ion o he i e a i e scheme. Mo eo e , we also assume
ha (
M
(0)
)


R
(0)

1. Then, one can sol e (
eq
1
)
;
(
eq
5
)as ollows:
34
No mal Beha iou o Lowe Dimensional To i
(
eq
1
) Fo
d
,we ha e
d
(

)=
X
k
2
Z
+
m
1
n
0
g
a
k
ik
>
!
exp(
ik
>

)

ha implies,
k
d
k
E
(1)

(0)
;

(0)




(0)
exp (1)
!

k
~
a
k
E
(1)

(0)

(0)

^
N
(
M
(0)
)
1
;

;

:
(
eq
2
) Fo any
j
,1

j

2(
m
;
m
1
), we ha e
e
j
(

)=
X
k
2
Z
+
m
1
b
jk
ik
>
!
+
^

(0)
j
exp(
ik
>

)

and hence,
k
e
k
E
(1)

(0)
;

(0)


2

1
+



(0)
exp (1)
!

1

(0)
!
k
b
k
E
(1)

(0)

^
N
(
M
(0)
)
1
;
2

;

:
(
eq
3
) Taking a e age wi h esp ec o

, we ob ain

=(
C
(0)
)
;
1
0
@
c
;
!
; C
(0)

@d
@
!
>
1
A
:
Thus,
k

k
E
(1)
=
k
(
C
(0)
)
;
1
C
(0)

k
E
(1)
k
(
C
(0)
)
;
1
k
E
(1)
k
C
(0)

k
E
(1)


m
0
B
@
k
c
;
!
k
E
(1)

0
+






C
(0)

@d
@
!
>






E
(1)

0
1
C
A


m

k
c
;
!
k
E
(1)

(0)
+ ^
m
k
d
k
E
(1)

(0)
;

(0)
(

(0)
;

(0)
) exp (1)
!

^
N
(
M
(0)
)
1
;

;

:
Tosol e he equa ion o
, we dene
c

=~
c
;
~
C
(0)

;C
(0)

@d
@
!
>
+
C
(0)

@d
@
!
>

and hen, o any 1

j

+
m
1
, we ha e
j
(

)=
X
k
2
Z
+
m
1
n
0
g
c

jk
ik
>
!
exp(
ik
>

)
:
To b ound
,  s we ha e ha
k
c

k
E
(1)

(0)
;
2

(0)
 k
~
c
k
E
(1)

(0)
+
kC
(0)
k
E
(1)

(0)

k

k
E
(1)
+
k
d
k
E
(1)

(0)
;

(0)

(0)
exp (1)
!


^
N
(
M
(0)
)
1
;
2

;


and om he e
k
k
E
(1)

(0)
;
3

(0)




(0)
exp (1)
!

k
c

k
E
(1)

(0)
;
2

(0)

(0)

^
N
(
M
(0)
)
1
;
3

;
2

:
A. Jo ba and J. Villanue a
35
(
eq
4
) We dene
B

=
B

;J
m
;
m
1
(
B

), and hen, i
G
= (
G
jl
), 1

j l

2(
m
;
m
1
),
we ha e
G
jl
(

)=
X
k
2
Z
+
m
1
B

jlk
ik
>
!
+
^

(0)
j
+
^

(0)
l
exp(
ik
>

)
:
In his sum we ha e o a oid he indices (
j l  k
) o which
j
j
;
l
j
=
m
;
m
1
and
k
=0. In hese cases weha e i ial ze o di iso s, bu also he co ecien
B

jl
0
is 0.
Mo eo e , we ema k ha he ma ix
G
is symme ic. Then, o bound
G
, we ha e
o b ound
B

. Fi s , we ha e
k
B

;
^
B
(0)

k
E
(1)

(0)
;
2

(0)
k
B
;
^
B
(0)

k
E
(1)

(0)
;
2

(0)
+
+(2(
m
;
m
1
)+1)(
+
m
1
)
k
H
(0)

k
E
(1)

(0)
R
(0)
(
R
(0)
)
4

k

k
E
(1)
+
k
d
k
E
(1)

(0)
;

(0)

(0)
exp (1)
!
+
+24(
m
;
m
1
)
2
k
H
(0)

k
E
(1)

(0)
R
(0)
(
R
(0)
)
3
k
e
k
E
(1)

(0)
;

(0)

^
N
(
M
(0)
)
1
;
6

;


and om he deni ion o
B

and he no m used, he same bound holds o
B

.
Then,
k
G
k
E
(1)

(0)
;
3

(0)


1

1
+



(0)
exp (1)
!

1

(0)
!
2(
m
;
m
1
)
k
B

k
E
(1)

(0)
;
2

(0)


^
N
(
M
(0)
)
1
;
7

;
2

:
(
eq
5
)The die en comp onen s o
F
a e gi en by
F
jl
(

)=
X
k
2
Z
+
m
1
E

jlk
ik
>
!
+
^

(0)
l
exp(
ik
>

)

o
j
=1
:::
+
m
1
and
l
=1
:::
2(
m
;
m
1
). Thus,
k
E

k
E
(1)

(0)
;
2

(0)
k
E
k
E
(1)

(0)
+2(
m
;
m
1
)
kC
(0)
k
E
(1)

(0)
k
e
k
E
(1)

(0)
;

(0)

(0)
exp (1)
+
+4(
m
;
m
1
)(
+
m
1
)
k
H
(0)

k
E
(1)

(0)
R
(0)
(
R
(0)
)
5

k

k
E
(1)
+
k
d
k
E
(1)

(0)
;

(0)

(0)
exp (1)
!
+
+8(
m
;
m
1
)
2
k
H
(0)

k
E
(1)

(0)
R
(0)
(
R
(0)
)
4
k
e
k
E
(1)

(0)
;

(0)

^
N
(
M
(0)
)
1
;
7

;


and, hence,
k
F
k
E
(1)

(0)
;
3

(0)


2

1
+



(0)
exp (1)
!

1

(0)
!
2(
m
;
m
1
)
k
E

k
E
(1)

(0)
;
2

(0)


^
N
(
M
(0)
)
1
;
8

;
2

:
We use hese es ima es o b ound he ans o med Hamil onian
H
(1)
. Fo his pu p ose, we
dene
H
(0)

:=
H
(0)
S
g
=
H
(0)

1
+
H
(0)

2
,wi h
H
(0)

1
=

!
>
I
+
1
2
^
Z
>
^
B
(0)

^
Z
+
1
2
I
>
C
(0)
I
+
H
(0)

S


36
No mal Beha iou o Lowe Dimensional To i
and
H
(0)

2
=
^
H
(0)
S
g
. No e ha we a e spli ing he con ibu ions ha a e
O
1
(
^
H
(0)
) and
O
2
(
^
H
(0)
). Then, by cons uc ion o
S
,one has
H
(0)
+
H
(0)

1
=

(1)
+
!
>
I
+
1
2
^
Z
>
^
B
(1)

^
Z
+
1
2
I
>
C
(1)
(

)
I
+
H
(1)


wi h
^
B
(1)

=
J
m
;
m
1
(
^
B
(1)

) and
<H
(1)

>
=0. Hence,
H
(1)
akes he same o m as
H
(0)
in
(60) i we dene
^
H
(1)
=
H
(0)

!
S
1
;
H
(0)
;
H
(0)

1
=
Z
1
0

H
(0)

2
+(1
;
)
H
(0)

1
S
g


!
S
d :
(70)
To b ound he die en e ms o
H
(1)
, we use Lemma 6 o b ound he Poisson b acke s
in ol ed in he p e ious exp essions:
k
H
(0)

1
k
E
(1)

(0)
;
4

(0)
R
(0)
exp (
;

(0)
)

^
N
(
M
(0)
)
1
;
12

;
2


k
H
(0)

1
S
gk
E
(1)

(0)
;
5

(0)
R
(0)
exp (
;
2

(0)
)

^
N
(
M
(0)
)
2
;
24

;
4


k
H
(0)

2
k
E
(1)

(0)
;
4

(0)
R
(0)
exp (
;

(0)
)

^
N
(
M
(0)
)
2
;
12

;
2

:
Hence, o b ound
^
H
(1)
one only needs o con ol he eec o !
S
. To his end, we ema k
ha om he b ounds on he solu ions o (
eq
1
)
;
(
eq
5
), one has
k
S
k
E
(1)

(0)
;
4

(0)
R
(0)

^
N
(
M
(0)
)
1
;
9

;
2


(71)
whe e
S
is aken wi h esp ec o (

^
X I
^
Y
). I we assume ha
k
S
k
E
(1)

(0)
;
4

(0)
R
(0)

(
R
(0)
)
2

(0)
exp (
;
1)
=
2

(72)
hen, !
S
is well dened om
D
+
m
1
m
;
m
1
(

(0)
;
5

(0)
R
(0)
exp (
;

(0)
)) o
D
+
m
1
m
;
m
1
(

(0)
;
4

(0)
R
(0)
), o any
;
1


1, and o any
!
2 E
(1)
( his ollows om Lemma 9 and
(27)). Mo e p ecisely, we ha e ha
k
!
S
;
Id
k
E
(1)

(0)
;
5

(0)
R
(0)
exp (
;

(0)
)
k
S
k
E
(1)

(0)
;
4

(0)
R
(0)

(73)
o any
;
1


1. F om (71) weha e ha (72) holds i
^
N
(
M
(0)
)
1
;
12

;
2


1, condi ion
ha will ollow immedia ely om he induc i e es ic ions. Applying he b ounds (71),
(71) and (73) o (70) and using Lemma 7, we deduce
k
^
H
(1)
k
E
(1)

(0)
;
6

(0)
R
(0)
exp (
;
3

(0)
)

^
N
(
M
(0)
)
2
;
24

;
4

:
(74)
Mo eo e , he b ound on
H
(0)

1
p o duces
k

(1)
;

(0)
k
E
(1)

^
N
(
M
(0)
)
1
;
12

;
2


k
^
B
(1)

;
^
B
(0)

k
E
(1)

^
N
(
M
(0)
)
1
;
14

;
2


kC
(1)
;C
(0)
k
E
(1)

(0)
;
4

(0)

^
N
(
M
(0)
)
1
;
16

;
2


k
H
(1)

;
H
(0)

k
E
(1)

(0)
;
4

(0)
R
(0)
exp (
;

(0)
)

^
N
(
M
(0)
)
1
;
12

;
2

:
(75)
We ake
N

6, and we dene

(1)
=

(0)
;
N
(0)
,and
R
(1)
=
R
(0)
exp (
;
(
N
;
3)

(0)
).
Then, i is no dicul o ew i e he bounds on
H
(1)
as he ones on
H
(0)
, bu now on
D
+
m
1
m
;
m
1
(

(1)
R
(1)
). To i e a e his scheme, we only need o check ha he b ounds
assumed on
H
(0)
o dene
^
N
s ill hold on
H
(1)
. This is done in he nex sec ion.
A. Jo ba and J. Villanue a
37
4.3.3 Con e gence o he i e a i e scheme
Lo oking a he b ounds o he p e ious sec ion, we ake
>
0 small enough such ha , o
s
=2(1
;
16

;
2

), weha e
s>
1. Then, assuming
^
N

1, wedene
M
(1)
=(
^
NM
(0)
)
s
(no e ha his is a b ound o he no m o
^
H
(1)
in (74)). I he hyp o heses needed o
i e a e hold, we ob ain ecu si ely
M
(
n
)
= (
^
NM
(0)
)
s
n
, and hence, o
R
small enough,
we ha e lim
n
!1
M
(
n
)
= 0. Le us dene
E

(
R
)as he se o pa ame e s
!
o which
all he s eps a e well dened. We assume ha , o any
!
2 E

(
R
), he comp osi ion o
canonical ans o ma ions !

= !
S
(0)
1

!
S
(1)
1

:::
(b eing
S
(
n
)
he gene a ing unc ion
used a he
n
-s ep o he i e a i e p o cedu e) is con e gen . Then, he limi Hamil onian
H

=
H
(0)

!

akes he o m:
H

=


(
!
)+
!
>
I
+
1
2
^
Z
>
^
B

(
!
)
^
Z
+
1
2
I
>
C

(
 !
)
I
+
H


(

^
X I
^
Y!
)

wi h
< H


>
=0. This is, we ob ain o any
!
2 E

a Hamil onian wi h an (
+
m
1
)-
dimensional educible o us, wi h linea quasip e io dic ow gi en by
!
.
Le us p o e ha he induc i e bounds hold. Fi s , we check ha we can dene,
ecu si ely, cons an s
m
(
n
)
, ^
m
(
n
)
,

(
n
)
1
,

(
n
)
2
and ^

(
n
)
, eplacing he ini ial sup e - (0)"
ones, such ha hey a e also b ounded by
m
, ^
m
,

1
,

2
and ^

, esp ec i ely. Top o e ha ,
we no e ha he exp essions in he igh -hand side o (75) can b e b ounded by(
^
NM
(0)
)
s=
2
(we ema k ha he same b ound holds o (71)). Hence, i e a ing his bounds, we only
need o use ha he sum
X
n

0

^
NM
(0)

s
n
+1
2

(76)
is con e gen o
R
small enough (and in ac , ha i go es o ze o when
R
do es), o
jus i y hese
n
-indep enden b ounds. The same a gumen s can be used o p o e ha
k


k
E

<
+
1
. He e, we only check he b ound
m
(
n
)

m
, b ecause is he only one ha
do es no ollow di ec ly: no e ha one can dene
m
(1)
=
m
(0)
1
;
m
(0)
(
^
NM
(0)
)
s=
2

and hen, aking
R
small enough, weha e
m
(1)

m
. Hence, i e a ing his deni ion and
assuming
m
(
n
)

m
by induc ion, we ha e
m
(
n
)

m
(0)
n
;
1
Y
j
=0
1
1
;
m
(
^
NM
(0)
)
s
n
+1
=
2
:
Unde his induc i e hyp o esis, one can b ound
m
(
n
)
by an inni e p o duc ha i is
con e gen b ecause (76) do es. F om he e, he b ound
m
(
n
)

m
ollows immedia ely o
R
small enough. Finally, wi h he induc i e deni ions

(
n
+1)
=

(
n
)
;
N
(
n
)
and
R
(
n
+1)
=
R
(
n
)
exp (
;
(
N
;
3)

(
n
)
),
n

0, we need o check ha

(
n
)


0
=
4and
R
(
n
)

M
(
n
)
. We
ema k ha , as we ake

(
n
)
=(
M
(
n
)
)

, we ha e,
X
n

0

(
n
)

(
M
(0)
)

+
X
n

1
(
^
NM
(0)
)
s
n


2(
M
(0)
)


(77)
a leas o
R
small enough. Then, as
N
will be a xed numb e , he b ound on

(
n
)
is
clea , aking
R
small enough. Mo eo e , wealsoha e
R
(
n
)

R
(0)
exp (
;

0
=
4)
>R
(0)
=
2=

38
No mal Beha iou o Lowe Dimensional To i
M
(0)

M
(
n
)
. To jus i y his las inequali y, we only need o ake
R
small enough such
ha
M
(1)

M
(0)
. Unde his assump ion, he sequence
M
(
n
)
g
n

0
is clea ly dec easing.
Finally, o p o e he well dened cha ac e o he limi Hamil onian, i only emains
o check he con e gence o !

. To do ha we w i e, o simplici y, !
(
n
)
= !
S
(
n
)
1
and
we dene
(
!
(
n
)
= !
(0)

:::

!
(
n
)
, o
n

0. We also pu

0
n
=

(
n
)
;

0
=
8 and
R
0
n
=
R
(
n
)
exp (
;

0
=
8),
n

1. Then, using in induc i e o m he b ounds (73), (71) and (72), i
is no dicul o check ha om Lemma 8 we ha e
k
(
!
(
n
+1)
;
(
!
(
n
)
k
E


0
n
+2
R
0
n
+2


(1 +
^
"(
^
NM
(0)
)
s
2
;
2

)
k
!
(1)

:::

!
(
n
+1)
;
!
(1)

:::

!
(
n
)
k
E


0
n
+2
R
0
n
+2

whe e
^
"only dep ends on
,
m
,
m
1
,

0
and
^
N
. I e a ing his b ound and aking

small
enough, one ob ains o
R
small enough
k
(
!
(
n
+1)
;
(
!
(
n
)
k
E


0
n
+2
R
0
n
+2

n
Y
j
=0
(1 +
^
"(
^
NM
(0)
)
s
j
+1
2
;
2

)(
^
NM
(0)
)
s
n
+2
2

2(
^
NM
(0)
)
s
n
+2
2

whe e we ha e used again he con e gen cha ac e o he sum (76). F om his b ound, i
is clea ha i
p>q

0, hen
k
(
!
(
p
)
;
(
!
(
q
)
k
E


0
=
8
R
(0)
exp (
;
3

0
=
8)

X
j

q
2(
^
NM
(0)
)
s
n
+2
2

bound ha goes oze o as
p q
!
+
1
.This allows o check ha he limi canonical ans-
o ma ion !

go es om
D
+
m
1
m
;
m
1
(

0
=
8
R
(0)
exp (
;
3

0
=
8)) o
D
+
m
1
m
;
m
1
(

(0)
R
(0)
).
4.3.4 Bounds on he measu e
Then, weha e shown he exis ence o eal in a ian educible o i o a se o pa ame e s
!
2E

.I only emains o b ound he measu e o
E

o , equi alen ly, he measu e o he
complemen a y se . To do ha , we s a ecalling how
E

is cons uc ed. I e a ing he
deni ion o
E
(1)
om
E
(0)
,we dene
E
(
n
+1)
om
E
(
n
)
in he same way as i has b een done
in (69), eplacing

(0)

(
M
(0)
)

by

(
n
)

(
M
(
n
)
)

. Then, we ha e
E

=
n

1
E
(
n
)
. This
is,
E

is cons uc ed by aking ou , in ecu si e o m, he se o pa ame e s
!
o which
he Diophan ine condi ions (69), o mula ed on he eigen alues o he p e ious s ep and
dep ending on he size o he emaining p e u ba i e e ms, do no hold. Then, he se o
emo ed pa ame e s can b e ob ained as union o se s o which one o hose condi ions is
no sa ised a some s ep o he i e a i e p o cess.
To es ima e he size o he emo ed se s, we will use a Lipschi z condi ion wi h esp ec
o
!
o he die en eigen alues
^

(
n
)
j
o
B
(
n
)

, o
n

0. To his end, we will p o e
ha his kind o egula i y holds o he successi e ans o med Hamil onians. As his
condi ion holds o he ini ial one, we ha e o check, by induc ion, ha he canonical
ans o ma ions used p ese e his kind o dep endence. The key poin is o b ound he
Lipschi z cons an s o he die en solu ions o (
eq
1
)
;
(
eq
5
). To do i , we ecall ha
we ha e b ounds like he ones o (68) o he Lipschi z cons an s o he die en e ms o
he decomp osi ion (60) o
H
(0)
.Then, we only ha e o p o e ha hose bounds o he
Lipschi z cons an s, can be i e a ed in he same way as he b ounds on he no ms. To
see ha , we can use he die en esul s gi en in i em (
a
)o Lemma 11 o b ound he
A. Jo ba and J. Villanue a
39
Lipschi z cons an s o he solu ions o (
eq
1
)
;
(
eq
5
). We ema k ha , o he denomina o s
ha app ea sol ing hese equa ions, we ha e
L
E
(0)
ik
>
!
+
l
>
^

(0)
gj
k
j
1
+

(0)
1
j
l
j
1
:
Then, combining Lemma 11 wi h s anda d inequali ies o b ound he Lipschi z cons an s o
sums and p o duc s, i is no dicul o check ha one can i e a e b ounds o he ollowing
o m:
L
E
(1)

(1)
R
(1)
^
H
(1)
g 
~
N
(
M
(0)
)
2
s
1

L
E
(1)

(1)
R
(1)
^
B
(1)

;
^
B
(0)

g 
~
N
(
M
(0)
)
s
1

L
E
(1)

(1)
R
(1)
C
(1)
;C
(0)
g 
~
N
(
M
(0)
)
s
1

L
E
(1)

(1)
R
(1)
H
(1)

;
H
(0)

g 
~
N
(
M
(0)
)
s
1

ha a e analogous o he ones o (74) and (75).
~
N

1 dep ends on he same pa ame e s
as
^
N
, plus ~
m
, ~

and

1
. Mo eo e , aking

small enough, we ha e 2
s
1
>
1. He e, he
selec ion o
N
(used o dene

(1)
and
R
(1)
) is done dep ending on he numb e o imes ha
we need o use Cauchy es ima es o bound he die en no ms and Lipschi z cons an s.
I e a ing hose exp essions, i is no dicul o check (by induc ion) ha we can dene
induc i ely ~
m
(
n
)
, ~

(
n
)
and

(
n
)
1
o which he assumed
n
-indep enden bounds hold. The
deduc ion o hose Lipschi z b ounds is edious bu i only in ol es simple inequali ies.
Full de ails in a e y simila con ex can be ound in 10] o 11].
Le us pa icula ize hose b ounds on he eigen alues o
B
(
n
)

.I we expand
^

(
n
)
j
,
j
=1
:::
2(
m
;
m
1
),
n

0, as in (66), eplacing only he sup e sc ip (0)"by (
n
)", we
ha e ha
L
E
(
n
)
(

(
n
)
j
g
(
NR
, b eing
(
N
a p osi i e cons an indep enden om
R
,
j
and
n
.
To jus i y his asse ion, we no e ha i holds o
n
=0, and ha he con ibu ions ha
come om he nex s eps a e exp onen ially small wi h
R
.
Those b ounds on he Lipschi z cons an s o

(
n
)
j
plus he nondegene acy condi ions
(66) a e he key o con ol he measu e o
E
(
n
)
nE
(
n
+1)
. We conside he decomp osi ion
E
(
n
)
nE
(
n
+1)
=

l
2
Z
2(
m
;
m
1
)
0
<
j
l
j
1

2
l
^
X
6
=
l
^
Y

k
2
Z
+
m
1
n
0
g
R
(
n
)
lk

wi h
R
(
n
)
lk
(
R
)=
(
!
2E
(
n
)
(
R
):
j
ik
>
!
+
l
>
^

(
n
)
(
!
)
j
<

(
n
)
(
R
)
j
k
j

1
)
:
To es ima e he measu e o
R
(
n
)
lk
,we ake
!
(1)
and
!
(2)
in his se and hen, we ha e
j
ik
>
(
!
(1)
;
!
(2)
)+
l
>
(
^

(
n
)
(
!
(1)
)
;
^

(
n
)
(
!
(2)
))
j
<
2

(
n
)
j
k
j

1
:
Le us s a wi h he case
j
l
j
1
= 1. Then,
l
>
^

(
n
)
=
^

(
n
)
j
o some
j
= 1
:::
2(
m
;
m
1
).
Hence, he p e ious exp ession can be ew i en as
j
i
(
k
+
j
)
>
(
!
(1)
;
!
(2)
)+
(

(
n
)
j
(
!
(1)
)
;
(

(
n
)
j
(
!
(2)
)
j
<
2

(
n
)
j
k
j

1
:
40
No mal Beha iou o Lowe Dimensional To i
Assuming ha
!
(1)
;
!
(2)
is pa allel o
k
+Re(
j
), we ha e
j
!
(1)
;
!
(2)
j
2
=
j
(
k
+ Re(
j
))
>
(
!
(1)
;
!
(2)
)
j
j
k
+Re(
j
)
j
2

j
(
k
+
j
)
>
(
!
(1)
;
!
(2)
)
j
j
k
+ Re(
j
)
j
2


1
j
k
+ Re(
j
)
j
2

j
(

(
n
)
j
(
!
(1)
)
;
(

(
n
)
j
(
!
(2)
)
j
+
2

(
n
)
j
k
j

1
!


1
j
k
+ Re(
j
)
j
2

(
NR
j
!
(1)
;
!
(2)
j
+
2

(
n
)
j
k
j

1
!
:
b eing
j
:
j
2
he Euclidean no m o a eal ec o . Using ha Re(
j
)
6
= 0 (see (66)), we ob ain
ha he e exis s aposi i e cons an $
1
, indep enden om
j
,
k
and
n
,such ha
j
!
(1)
;
!
(2)
j
2

$
1

(
n
)
j
k
j

1

o
R
small enough. In ac , his bound can be ex ended o he case
j
l
j
1
= 2,
l
x
6
=
l
y
,
using ha Re(
j
1
j
2
)
6
=0 i
j
1
6
=
j
2
.This is abound o he wid h o a sec ion o
R
(
n
)
lk
by
a line in he di ec ion
k
+ Re(
j
). Then, he measu e o
R
(
n
)
lk
can be bounded by
mes(
R
lk
)

$
1

(
n
)
j
k
j

1

p
+
m
1
1
4
(
jC
;
1
j
)
;
1
R
2

+
m
1
;
1

whe e 2
p
+
m
1
1
8
(
jC
;
1
j
)
;
1
R
2
is a bound o he diame e o
E
(0)
(
R
). Then, we ha e
mes(
E
(
n
)
nE
(
n
+1)
)

$
2
R
2(
+
m
1
;
1)

(
n
)
X
k
2
Z
+
m
1
n
0
g
1
j
k
j

1

whe e $
2
do es no dep end on
n
and
R
. Using ha #
k
2
Z
+
m
1
:
j
k
j
1
=
j
g 
2(
+
m
1
)
j
+
m
1
;
1
and ha
>
+
m
1
we ob ain
mes(
E
(
n
)
nE
(
n
+1)
)

$
2
R
2(
+
m
1
;
1)

(
n
)
X
j

1
2(
+
m
1
)
j
+
m
1
;
1
;


$
3
R
2(
+
m
1
;
1)

(
n
)

b eing $
3
also indep enden om
n
and
R
. As

(
n
)
=(
M
(
n
)
)

,we deduce, using (77), ha
o
R

1 small enough,
mes(
E
(0)
nE

)

$
3
R
2(
+
m
1
;
1)
0
@
(
M
(0)
)

+
X
n

1
(
^
NM
(0)
)
s
n

1
A

2$
3
(
M
(0)
)

:
Taking in o accoun he b ound on he measu e o
W

1
8
(
jC
;
1
j
)
;
1
R
2

nE
(0)
(weha e shown,
om (61), ha i is o o de (
M
(0)
)
2

), one ob ains he exp onen ially small b ounds on
he measu e o des oyed o i. To nish he p o o , we dene
A
as

0
<R

R

E

(
R
), whe e
R

is he maximum alue o
R
o which he i e a i escheme con e ges.
5 Basic lemmas
In his sec ion, we gi e some basics esul s used o bound he no ms (12) and (13) and
he ela ed Lipschi z cons an s, as well as he exp essions and ans o ma ions in ol ed
in he die en p o o s. Simila lemmas app ea in 11].
A. Jo ba and J. Villanue a
41
Lemma 4
Le
(

)
and
g
(

)
be analy ic unc ions o
complex a gumen s dened on a
s ip o wid h
 >
0
,
2

-pe iodic on

, and aking alues in
C
. Le us deno e by
k
he
Fou ie coecien s o
,
=
P
k
2
Z
k
exp (
ik
>

)
. Then, we ha e:
(
i
)
j
k
jj
j

exp (
;j
k
j
1

)
.
(
ii
)
j
g
j

j
j

j
g
j

.
(
iii
)
Fo e e y
0
< <
,





@
@
j






;


j
j


exp (1)
 j
=1
::: :
(
i
)
Le
d
k
g
k
2
Z
n
0
g

C
, wi h
j
d
k
j

j
k
j

1
, o some
>
0
and


0
. I we assume ha
=0
, hen, o any
0
< <
, we ha e ha he unc ion
g
dened as
g
(

)=
X
k
2
Z
n
0
g
k
d
k
exp (
ik
>

)

sa ises he bound
j
g
j

;





exp(1)
!

j
j


:
All hese bounds can be ex ended o he case in which
and
g
ake alues in
C
n
1
o
M
n
1
n
2
(
C
)
.
P o o :
I ems
(i)
and
(ii)
a e easily e ied. P o o s o
(iii)
and
(i )
ollows immedia ely
using (23).
Lemma 5
Le
(
 x I  y
)
and
g
(
  x I  y
)
be analy ic unc ions on
D
m
(
 R
)
, and
2

-
pe iodic on

. Then,
(
i
)
I
=
P
(
ls
)
2
N
2
m

N
ls
(

)
z
l
^
I
s
,we ha e
j
ls
j


j
j
R
R
j
l
j
1
+2
j
s
j
1
.
(
ii
)
j
g
j
R
j
j
R
j
g
j
R
.
(
iii
)
Fo e e y
0
< <
and
0
<<
1
,we ha e o
j
=1
:::
and
k
=1
:::
2
m
:





@
@
j






;
R

j
j
R

exp(1)






@
@I
j





R

j
j
R
(1
;

2
)
R
2






@
@z
k





R

j
j
R
(1
;

)
R
:
As in Lemma
4
, al l he bounds hold i
and
g
ake alues in
C
n
1
o
M
n
1
n
2
(
C
)
.
P o o :
The p o o o
(i)
and
(ii)
is s aigh o wa d.
(iii)
is p o ed using i em
(iii)
o
Lemma 4 and applying Cauchy es ima es o he unc ion
P
(
ls
)
2
N
2
m

N
j
ls
j

z
l
^
I
s
.
Lemma 6
Le us conside
(
  x I  y
)
and
g
(
  x I  y
)
complex- alued unc ions, such
ha
and
g
a e analy ic unc ions dened on
D
m
(
 R
)
,
2

-pe iodic on

. Then, o
e e y
0
< <
and
0
<<
1
, we ha e:
j
 g
gj

;
R

j
j
R

exp (1)





@g
@I






;
R
+
j
j
R
R
2
(1
;

2
)





@g
@






;
R
+
2
m
j
j
R
R
(1
;

)





@g
@z






;
R
: