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Asymptotic behavior of stochastic delay Navier-Stokes equations on unbounded domains

Zhang, Qiangheng; Caraballo Garrido, Tomás; Yang, Shuang

Abstract

In this paper, the random dynamics of non-autonomous stochastic Navier-Stokes equations with variable delays on unbounded Poincaré domains is analysed. First, we establish the existence, uniqueness and backward compactness of pullback random attractors. Second, we study the upper semicontinuity of pullback random attractors as the delay time tends to zero. Finally, we investigate the backward asymptotic autonomy of pullback random attractors. Due to the non-compactness of Sobolev embeddings on unbounded domains, we introduce a stream function to prove backward uniform tailends smallest of solutions, and then establish the backward asymptotic compactness of the solution operators.

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COMMUN. MATH. SCI. ©2025 In e na ional P ess Vol. 23, No. 4, pp. 1139–1166 ASYMPTOTIC BEHAVIOR OF STOCHASTIC DELAY NAVIER-STOKES EQUATIONS ON UNBOUNDED DOMAINS∗ QIANGHENG ZHANG†, TOM´ AS CARABALLO‡,AND SHUANG YANG§ Abs ac . In his pape , he andom dynamics o non-au onomous s ochas ic Na ie -S okes equa- ions wi h a iable delays on unbounded Poinca ´e domains is analysed. Fi s , we es ablish he exis ence, uniqueness and backwa d compac ness o pullback andom a ac o s. Second, we s udy he uppe semi- con inui y o pullback andom a ac o s as he delay ime ends o ze o. Finally, we in es iga e he backwa d asymp o ic au onomy o pullback andom a ac o s. Due o he non-compac ness o Sobole embeddings on unbounded domains, we in oduce a s eam unc ion o p o e backwa d uni o m ail- ends smalles o solu ions, and hen es ablish he backwa d asymp o ic compac ness o he solu ion ope a o s. Keywo ds. Na ie -S okes equa ions; Delay; Unbounded domain; Pullback andom a ac o ; S eam unc ion. AMS subjec classi ica ions. 35B40; 35B41; 37L55; 60H15. 1. In oduc ion In his pape , we conside he s abili y o pullback andom a ac o s o he ollow- ing s ochas ic non-au onomous Na ie -S okes equa ions wi h delays and mul iplica i e noise de ined on unbounded Poinca ´e domains:              du−(ν∆u−(u·∇)u−∇p)d =( (u( −ρ( )))+g( ,x))d +u◦dW, ∇·u=0, x∈O, > τ, u=0, x ∈∂O, > τ, u(τ+ξ):=ψ(ξ), ξ ∈[−ϱ,0], τ ∈R, (1.1) whe e he wo posi i e cons an s νand ϱs and o he kinema ic iscosi y and delay ime o he luid, espec i ely. u=(u1,u2) and pa e he eloci y ield and p essu e o he luid, espec i ely. ρ(·) deno es he delay unc ion. O ⊂R2is an unbounded Poinca ´e domain wi h bounda y ∂O, ha is, he e exis s a posi i e cons an λsuch ha λZO |u|2dx≤ZO |∇u|2dx, ∀u∈H1 0(O).(1.2) deno es he delay o cing, which is Lipschi z con inuous. gs ands o he non- au onomous o cing. Wis a wo-sided eal- alued Wiene p ocess on a p obabili y space (Ω,F,P ), whe e Ω ={ω∈C(R,R): ω(0) =0},Fis he Bo el σ-algeb a induced by he compac -open opology o Ω and Pis he co esponding Wiene measu e on (Ω,F). The symbol ◦deno es (1.1) is unde s ood in he S a ono ich in eg a ion. ∗Recei ed: June 05, 2024; Accep ed (in e ised o m): Decembe 02, 2024. Communica ed by Alexis F. Vasseu . †School o Ma hema ics and S a is ics, Heze Uni e si y, Heze 274015, P.R. China (zqh ma h@ 126.com). ‡Dp o. Ecuaciones Di e enciales y An´alisis Num´e ico, Facul ad de Ma em´a icas, Uni e sidad de Se illa, C/Ta ia s/n, 41012-Se illa, Spain; Depa men o Ma hema ics, Wenzhou Uni e si y, Wen- zhou, Zhejiang P o ince, 325035, P.R. China ([email p o ec ed]). §School o Ma hema ics and S a is ics, Huazhong Uni e si y o Science and Technology, Wuhan 430074, P.R. China (shuang-y[email p o ec ed]). 1139 RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL 1140 STOCHASTIC DELAY NAVIER-STOKES EQUATIONS Na ie -S okes equa ions a e impo an models in luid mechanics, which summa ize he gene al law o iscous luid low. In pas wo decades, Na ie -S okes equa ions wi h delays ha e ecei ed much a en ion. Ca aballo and Real [10,11] i s conside ed he 2D Na ie -S okes equa ions wi h delays and p o ed he exis ence and uniqueness o solu ions, and s udied he con e gence o solu ions o he s a iona y one. Since hen, he long- e m beha io o 2D Na ie -S okes equa ions wi h delays has been widely s udied (see [7,12,17–19,24–29,44] and he e e ences he ein). In [19], he au ho s es ablished he exis ence and uniqueness o solu ions as well as he exponen ial s abili y o s a iona y solu ions o 2D Na ie -S okes equa ions wi h delays on unbounded Poinca ´e domain. In [27], he au ho s used he ene gy equa ion me hod o p o e he exis ence o pullback a ac o s o 2D Na ie -S okes equa ions wi h delays on unbounded Poinca ´e domain. Howe e , he e is no esul epo ed in he li e a u e on he 2D s ochas ic Na ie -S okes equa ions wi h delays on unbounded Poinca ´e domain. Mo i a ed by [3,4,9,33,34,37, 38,44], we analyze he andom dynamics o 2D s ochas ic Na ie -S okes equa ions wi h delays and non-au onomous o cing on unbounded Poinca ´e domain. The i s goal o his pape is o p o e he exis ence and uniqueness o pullback andom a ac o s Aϱ={Aϱ(τ,ω):τ∈R,ω ∈Ω}and ha he backwa d compac ness o Aϱ:Ss≤τAϱ(s,ω) is p e-compac o all τ∈R. As we know, he asymp o ic compac - ness o solu ion ope a o s is a key s ep in p o ing he exis ence o a ac o s. How- e e , he Sobole embedding is non-compac on unbounded domains. To o e come his di icul y, we usually use he ene gy equa ion me hod es ablished in [1] and ail-ends es ima es me hod ini ia ed in [30]. In his wo k, we will use he backwa d uni o m ail- ends es ima es me hod. No e ha Na ie -S okes equa ions a e di e en om eac ion- di usion equa ions, and so we need o in oduce a s eam unc ion o change he ec o equa ion o a scala equa ion. Mo e p ecisely, le ηk(x) =η(|x|2 k2) o all x∈Ω, whe e η(·):[0,+∞)→[0,1] be a smoo h unc ion sa is ying η( )=(0,0≤ ≤1, 1, ≥4. I we mul iply (1.1) by η2 ku, hen we will encoun e a new p oblem: he p essu e e m ROηku∇pdx. This is because he incomp essible condi ion will be in alid, see Lemma 3.4 o mo e de ails. The second a ge o his pape is o conside he uppe semicon inui y o pullback andom a ac o s. I is easy o see ha we can ob ain di e en pullback andom a ac o o di e en delay ime in (1.1). Then, a na u al idea is o s udy he uppe semicon inui y o pullback andom a ac o s Aϱ={Aϱ(τ,ω): τ∈R,ω ∈Ω}: lim ϱ→0dis ϱ(Aϱ(τ,ω),A0(τ,ω))= 0,(1.3) whe e dis ϱ(A,B)=supa∈Ain b∈Bsupξ∈[−ϱ,0] ∥a(ξ)−b∥2and A0={A0(τ,ω):τ∈R,ω ∈ Ω}is a pullback andom a ac o o limi equa ion o (1.1). Recen ly, he heo e ical esul o (1.3) was es ablished in [36], and de eloped by [14,22,42] and he e e ences he ein. I is wo h poin ing ou ha we in oduce an in e se unc ion o o e come he di icul y caused by he a iable delay. The las goal o his pape is conce ned wi h he backwa d asymp o ic au onomy o pullback andom a ac o s Aϱ={Aϱ(τ,ω) :τ∈R,ω ∈Ω}: lim τ→−∞dis (Aϱ(τ,ω),A∞(ω))=0, RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL QIANGHENG ZHANG, TOM´ AS CARABALLO, AND SHUANG YANG 1141 whe e dis (·,·) deno es he Hausdo semi-dis ance and A∞={A∞(ω):ω∈Ω}is a an- dom a ac o o au onomous e sion o (1.1). The concep o pullback andom a ac- o s was in oduced in [8,16,31,32], which is a amily o se s pa ame e ized by ime and sample ω. Then, an in e es ing p oblem is de o ed o in es iga ing hei ime- dependen p ope ies (see [5,15,20,21,23,34,35,39,40,42–44]). Howe e , he e is no pape on he asymp o ic au onomy o pullback andom a ac o s o (1.1). 2. P elimina ies In his pape , we iden i y W( ) wi h ω( ) o all ∈Ron he p obabili y space (Ω,F,P ). De ine a ime shi θ by θ ω(·)=ω( +·)−ω( ) o all ∈Rand ω∈Ω, which along wi h (Ω,F,P ) o ms a me ic dynamical sys em (Ω,F,P,{θ } ∈R). We now es ab- lish a con inuous andom dynamical sys em o (1.1) o e (Ω,F,P,{θ } ∈R). To his end, we i s ans o m s ochas ic Equa ion (1.1) in o a andom equa ion. Le ( ,τ,ω,ϕ)=e−z(θ ω)u( ,τ,ω,ψ),wi h ϕ(ξ)=e−z(θτ+ξω)ψ(ξ),∀ξ∈[−ϱ,0],(2.1) whe e z(θ ω)=−R0 −∞ e (θ ω)( )d o all ∈R, which is a solu ion o O ns ein- Uhlenbeck equa ion: dz +zd =dω( ). In addi ion, by [2, P oposi ion 5.1] he e exis s a θ -in a ian subse Ω0⊂Ω ( o con enience, s ill deno ed as Ω) such ha 7→z(θ ω) is con inuous and lim →±∞ |z(θ ω)| | |=0,lim →±∞ R 0z(θ ω)d =0,∀ω∈Ω.(2.2) Subs i u ing (2.1) in o (1.1) yields he ollowing andom equa ion:                  ∂ ∂ −ν∆ +ez(θ ω)( ·∇) +e−z(θ ω)∇p =e−z(θ ω)( (ez(θ −ρ( )ω) ( −ρ( )))+g( ,x))+z(θ ω) , x ∈ O, >τ, ∇· =0, x ∈O, > τ, =0, x ∈∂O, > τ, (τ+ξ):=ϕ(ξ), ξ ∈[−ϱ,0], τ ∈R, (2.3) whe e he delay unc ion ρ(·) and delay e m (·,·) sa is y he ollowing assump ions: (D) ρ(·)≥0 sa is ies ρ(·)∈C1(R,R) and sup ∈R ρ( )=ϱ > 0,sup ∈R d d ρ( ) =ρ∗<1.(2.4) (F) (0)=0 and he e exis s a posi i e cons an L such ha | (s1)− (s2)|R2≤L |s1−s2|R2, o all s1,s2∈R2,(2.5) and ¯η:= νλ 2−2E(|z|)−L (1−ρ∗)1 2 eνλ 4ϱ(E(e2z(ω))+E(e−2z(ω)))>0,(2.6) whe e E(|z|) deno es he expec a ion o |z|. Le V={u∈(C∞ 0(O,R2))2:∇·u=0}. Suppose ha Pis a Le ay p ojec ion om L2(O) on o H, whe e His he closu e o Vin L2(O,R2) wi h he inne p oduc (·,·) and no m ∥·∥, de ined by (u, )=ZO u dx, ∥u∥2= (u,u), o all u, ∈H. RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL 1142 STOCHASTIC DELAY NAVIER-STOKES EQUATIONS Le Vbe he closu e o Vin H1 0(O,R2) wi h he inne p oduc ((·,·)) and no m ∥·∥V, de ined by ((u, ))= 2 X i,j=1ZO ∂ui ∂xj ∂ i ∂xj dx, ∥u∥2 V=((u,u)), o all u, ∈V. We use V′ o deno e he dual space Vand ⟨·,·⟩ he duali y pai ing be ween Vand V′. Applying P o (2.3), we ob ain      ∂ ∂ +νA +ez(θ ω)B( , ) =e−z(θ ω)P( (ez(θ −ρ( )ω) ( −ρ( )))+g( ,x))+z(θ ω) , x ∈ O, >τ, (τ+ξ):=ϕ(ξ), ξ ∈[−ϱ,0], τ ∈R, (2.7) whe e A =−P∆ wi h A:V→V′de ined by ⟨Au, ⟩=((u, )), and B( , )= P(( ·∇) ) wi h B:V×V→V′and ⟨B(u, ),w⟩=b(u, ,w), whe e b(u, ,w)= 2 X i,j=1ZO ui ∂ j ∂xi wjdx, o all u, ,w ∈V, (2.8) which sa is ies b(u, ,w)=−b(u,w, ) and b(u, , )=0.(2.9) Le CH=C([−ϱ,0];H) and CV=C([−ϱ,0];V) wi h no m ∥u∥CH= sup ξ∈[−ϱ,0] ∥u(ξ)∥and ∥u∥CV= sup ξ∈[−ϱ,0] ∥u(ξ)∥V. In [19], he au ho s p o ed he exis ence and uniqueness o solu ions o 2D Na ie -S okes equa ions wi h he abs ac delay e m. No e ha (2.7) is a de e minis ic equa ion pa ame e ized by ω. Hence we need o show ha he a iable delay e m sa is ies he assump ions (I)-(IV) o he abs ac delay e m in [19]. By (D) and (F), i is easy o see ha (I) and (II) hold. By (2.4) and (2.5) we ob ain o all u, ∈CH, ∥ (u( −ρ( )))− ( ( −ρ( )))∥2=ZO | (u( −ρ( )))− ( ( −ρ( )))|2 R2dx ≤L2 ∥u( −ρ( ))− ( −ρ( ))∥2≤L2 ∥u − ∥2 CH, which implies ha (III) holds. By (2.4) and (2.5) again, we ob ain o all u, ∈C([τ− h, ];H) and ≥τ, Z τ ∥ (u( −ρ( )))− ( ( −ρ( )))∥2d ≤L2 Z τ ∥u( −ρ( ))− ( −ρ( ))∥2d ≤L2 1−ρ∗Z τ−ϱ ∥u( )− ( )∥2d , which implies ha (IV) holds. We ema k ha (2.7) is an abs ac o m o (2.3). Then we de i e (2.3) has a unique solu ion ∈C([τ−ϱ,T ];H)∩L2(τ,T;V) o all T > τ when RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL QIANGHENG ZHANG, TOM´ AS CARABALLO, AND SHUANG YANG 1143 ϕ∈CHand g∈L2 loc(R;(L2(O))2). We de ine a delay-shi by (ξ)= ( +ξ) o all ≥τand ξ∈[−ϱ,0], and conside a mapping Φ:R+×R×Ω×CH→CHby Φ( ,τ,ω)ψ=u +τ(·,τ,θ−τω,ψ)= +τ(·,τ,θ−τω,ϕ)ez(θ +·ω),(2.10) whe e is he solu ion o (2.3), which sa is ies (τ+ξ,τ,ω,ϕ)=ϕ. In addi ion, ( ,τ,ω,ϕ) is (F,B(H))-measu able wi h espec o ω, whe e B(H) s ands o he Bo el σ-algeb a o H. Then by (2.1) we imply he mapping Φ is a con inuous non-au onomous andom dynamical sys em associa ed wi h (2.1) in he sense o [31]. 3. Pullback andom a ac o s In his sec ion, we a e conce ned wi h he exis ence, uniqueness and backwa d compac ness o pullback andom a ac o s. Fo hese pu poses, we need o impose an assump ion abou he non-au onomous o cing g∈L2 loc(R;(L2(O))2), i.e., gis backwa d empe ed: sup s≤τZs −∞ eκ( −s)∥g( )∥2d :=G(τ)<+∞,∀τ∈R, κ > 0.(3.1) In o de o ea he delay e m, we now in oduce a andom a iable η(ω), which is de ined by η(ω)= νλ 2−2|z(ω)|− L (1−ρ∗)1 2 eνλ 4ϱ(e2z(ω)+e−2z(ω)).(3.2) Using he e godic heo em [6, Theo em 2.1] o (3.2), we in e om (2.6) lim →±∞ 1 Z 0 η(θlω)dl = ¯η. (3.3) We conside wo a ac ion uni e ses Dand Bin CH, gi en by D={D={D(τ,ω):τ∈R,ω ∈Ω}: lim →+∞e−κ ∥D(τ− ,θ− ω)∥2 CH=0},(3.4) and B={B={B(τ,ω):τ∈R,ω ∈Ω}: lim →+∞e−κ sup s≤τ ∥B(s− ,θ− ω)∥2 CH=0},(3.5) espec i ely. I is simple o imply ha Dand Ba e inclusion-closed, and B⊂D. Th oughou his pape , we assume ha he delay ime ϱ∈(0,ϱ0] o some ϱ0>0. F om now on, we assume ha cand C(ω) a e wo gene ic posi i e cons an s, whe e cis independen o ϱand ω, and C(ω) is uni o m wi h espec o ϱ. 3.1. Backwa d uni o m es ima es o solu ions. Lemma 3.1. Suppose ha (D) and (F) hold, and g∈L2 loc(R;(L2(O))2)is backwa d empe ed. Then we ob ain he ollowing conclusions: (i) Fo each τ∈R,ω∈Ωand D={D(τ,ω):τ∈R,ω ∈Ω}∈D, he e exis s a Td:= Td(τ,ω,D)≥3ϱ+3 such ha sup ξ∈[−3ϱ−3,0] ∥u(τ+ξ,τ − ,θ−τω,ψ)∥2≤cecϱ(1+Rd(τ,ω)) sup ξ∈[−3ϱ−3,0] e2z(θξω),(3.6) RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL 1144 STOCHASTIC DELAY NAVIER-STOKES EQUATIONS o all ≥Tdand ψ∈D(τ− ,θ− ω), whe e Rd(τ,ω)=Z0 −∞ eR 0η(θlω)dle−2z(θ ω)∥g( +τ)∥2d . (3.7) (ii) Fo each τ∈R,ω∈Ωand B={B(τ,ω): τ∈R,ω ∈Ω}∈B, he e exis s a Tb:= Tb(τ,ω,B)≥3ϱ+3 such ha sup s≤τ sup ξ∈[−3ϱ−3,0] ∥u(s+ξ,s− ,θ−sω,ψ)∥2≤cecϱ(1+Rb(τ,ω)) sup ξ∈[−3ϱ−3,0] e2z(θξω),(3.8) o all ≥Tband ψ∈B(s− ,θ− ω), whe e Rb(τ,ω)=sup s≤τ Rd(s,ω).(3.9) P oo . Taking he inne p oduc o (2.3) wi h ( ):= ( ,s− ,θ−sω,ϕ) in H, by he second equali y o (2.9) and he incomp essible condi ion we ob ain 1 2 d d ∥ ( )∥2+ν∥∇ ( )∥2 =e−z(θ −sω)( (ez(θ −ρ( )−sω) ( −ρ( )))+g( ), ( ))+z(θ −sω)∥ ( )∥2. Using he Young inequali y and (2.5), we ob ain e−z(θ −sω)( (ez(θ −ρ( )−sω) ( −ρ( )))+g( ), ( )) ≤L (1−ρ∗)1 2 2eνλ 4ϱe2z(θ −ρ( )−sω)∥ ( −ρ( ))∥2+L eνλ 4ϱ 2(1−ρ∗)1 2 e−2z(θ −sω)∥ ( )∥2 +νλ 4∥ ( )∥2+1 νλe−2z(θ −sω)∥g( )∥2. By (1.2) we ob ain ν∥∇ ( )∥2≥νλ 2∥ ( )∥2+ν 2∥∇ ( )∥2. Then we ha e d d ∥ ( )∥2+ν∥∇ ( )∥2 ≤L (1−ρ∗)1 2 eνλ 4ϱe2z(θ −ρ( )−sω)∥ ( −ρ( ))∥2+L eνλ 4ϱ (1−ρ∗)1 2 e−2z(θ −sω)∥ ( )∥2 +2 νλe−2z(θ −sω)∥g( )∥2+(2z(θ −sω)−νλ 2)∥ ( )∥2.(3.10) Mul iplying (3.10) by eR s− η(θl−sω)dl, and hen in eg a ing his esul o e [s− ,s+ξ] wi h ξ∈[−3ϱ−3,0] and ≥3ϱ+3 yields eRs+ξ s− η(θl−sω)dl∥ (s+ξ)∥2 ≤∥ϕ∥2 CH+L (1−ρ∗)1 2 eνλ 4ϱZs+ξ s− eR s− η(θl−sω)dle2z(θ −ρ( )−sω)∥ ( −ρ( ))∥2d RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL QIANGHENG ZHANG, TOM´ AS CARABALLO, AND SHUANG YANG 1145 +L eνλ 4ϱ (1−ρ∗)1 2Zs+ξ s− eR s− η(θl−sω)dle−2z(θ −sω)∥ ( )∥2d +2 νλ Zs+ξ s− eR s− η(θl−sω)dle−2z(θ −sω)∥g( )∥2d +Zs+ξ s− (2z(θ −sω)−νλ 2+η(θ −sω))eR s− η(θl−sω)dl∥ ( )∥2d . (3.11) I ollows om (2.4) and (3.2) ha L (1−ρ∗)1 2 eνλ 4ϱZs+ξ s− eR s− η(θl−sω)dle2z(θ −ρ( )−sω)∥ ( −ρ( ))∥2d ≤L (1−ρ∗)1 2eνλ 4ϱZs+ξ s− eR −ρ( ) s− η(θl−sω)dle2z(θ −ρ( )−sω)∥ ( −ρ( ))∥2d ≤L eνλ 4ϱ (1−ρ∗)1 2Zs+ξ s− −ϱ eR s− η(θl−sω)dle2z(θ −sω)∥ ( )∥2d =L eνλ 4ϱ (1−ρ∗)1 2 (Zs− s− −ϱ +Zs+ξ s− )eR s− η(θl−sω)dle2z(θ −sω)∥ ( )∥2d ≤L eνλ 4ϱ (1−ρ∗)1 2 ∥ϕ∥2 CHZs− s− −ϱ eR s− η(θl−sω)dle2z(θ −sω)d +L eνλ 4ϱ (1−ρ∗)1 2Zs+ξ s− eR s− η(θl−sω)dle2z(θ −sω)∥ ( )∥2d . (3.12) Then by (3.2) ( he de ini ion o η(ω)) we ob ain (2z(θ −sω)−νλ 2+η(θ −sω))+ L eνλ 4ϱ (1−ρ∗)1 2 (e−2z(θ −sω)+e2z(θ −sω)) =2z(θ −sω)−2|z(θ −sω)|≤0. Then by (3.11) and (3.12) we ha e ∥ (s+ξ)∥2≤ceR0 ξη(θlω)dl∥ϕ∥2 CH(e−R0 − η(θlω)dl +eνλ 4ϱZ− − −ϱ eR 0η(θlω)dl+2z(θ ω)d ) +ceR0 ξη(θlω)dl Z0 − eR 0η(θlω)dle−2z(θ ω)∥g( +s)∥2d ≤ce3νλ 2ϱe3νλ 2∥ϕ∥2 CH(e−R0 − η(θlω)dl +eνλ 4ϱZ− − −ϱ eR 0η(θlω)dl+2z(θ ω)d ) +ce3νλ 2ϱe3νλ 2Z0 − eR 0η(θlω)dle−2z(θ ω)∥g( +s)∥2d ≤ce2νλϱ∥ϕ∥2 CH(e−R0 − η(θlω)dl +Z− − −ϱ eR 0η(θlω)dl+2z(θ ω)d ) +ce2νλϱ Z0 − eR 0η(θlω)dle−2z(θ ω)∥g( +s)∥2d , (3.13) RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL 1146 STOCHASTIC DELAY NAVIER-STOKES EQUATIONS whe e we used η(ω)≤νλ 2in (3.2). F om (2.2) and (3.3), he e exis s a ˜ T:= ˜ T(¯η,ω)≥ 3ϱ+3 such ha o all | |≥ ˜ T, |z(θ ω)|≤ ¯η 16| |and Z 0 (η(θlω)−¯η)dl ≤¯η 2| |.(3.14) Then we ha e o all ≥˜ Tand ξ∈[−3ϱ−3,0], ∥ (s+ξ)∥2≤ce2νλϱ(e−¯η 2 +4 ¯ηe−¯ 3η 8 )∥ϕ∥2 CH+ce2νλϱ Z0 −∞ eR 0η(θlω)dle−2z(θ ω)∥g( +τ)∥2d . Hence by (2.1) we ob ain sup ξ∈[−3ϱ−3,0] ∥u(s+ξ)∥2 = sup ξ∈[−3ϱ−3,0] e2z(θξω)∥ (s+ξ)∥2 ≤ce2νλϱ sup ξ∈[−3ϱ−3,0] e2z(θξω)e−2z(θ− +ξω)(e−¯η 2 +4 ¯ηe−3¯η 8 )∥ψ∥2 CH +ce2νλϱ sup ξ∈[−3ϱ−3,0] e2z(θξω)Z0 −∞ eR 0η(θlω)dle−2z(θ ω)∥g( +τ)∥2d . (3.15) (i) When s=τ. I ψ∈D(τ− ,θ− ω), by (3.4) he e exis s a Td:=Td(τ,ω,D)≥˜ T such ha o all ≥Td, ce2νλϱe−2z(θ− +ξω)(e−¯η 2 +4 ¯ηe−3¯η 8 )∥ψ∥2 CH ≤ce(2νλ+3¯η 8)ϱe¯η 8 (e−¯η 2 +4 ¯ηe−¯η 4 )∥D(τ− ,θ− ω)∥2 CH≤ce(2νλ+¯η)ϱ, which implies ha (3.6) holds. (ii) I ψ∈B(s− ,θ− ω) wi h s≤τ, by (3.5) he e exis s a Tb:=Tb(τ,ω,B)≥˜ Tsuch ha o all ≥Td, ce2νλϱe−2z(θ− +ξω)(e−¯η 2 +4 ¯ηe−¯η 4 )sup s≤τ ∥ψ∥2 CH ≤ce(2νλ+3¯η 8)ϱe¯η 8 (e−¯η 2 +4 ¯ηe−¯η 4 )sup s≤τ ∥B(τ− ,θ− ω)∥2 CH≤ce(2νλ+¯η)ϱ, which, along wi h (3.15), shows ha (3.8) holds. The p oo is comple e. Lemma 3.2. Suppose ha (D) and (F) hold, and g∈L2 loc(R;(L2(O))2)is backwa d empe ed. Fo each τ∈R,ω∈Ωand B={B(τ,ω) :τ∈R,ω ∈Ω}∈ B, we ha e sup s≤τ sup ξ∈[−2ϱ−2,0] ∥∇u(s+ξ,s− ,θ−sω,ψ)∥2≤C(ω)¯ Rb(τ,ω)eC(ω)¯ R2 b(τ,ω),(3.16) o all ≥Tb(Tbis gi en by Lemma 3.1) and ψ∈B(s− ,θ− ω)wi h s≤τ, whe e ¯ Rb(τ,ω)=1+Rb(τ,ω)+G(τ). P oo . Taking he inne p oduc o (2.7) wi h A ( ) in H, by he incomp essible condi ion we ob ain 1 2 d d ∥∇ ( )∥2+ν∥A ( )∥2+ez(θ −s)b( ( ), ( ),A ( )) RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL QIANGHENG ZHANG, TOM´ AS CARABALLO, AND SHUANG YANG 1147 =e−z(θ −sω)( (ez(θ −ρ( )−sω) ( −ρ( ))),A ( )) e−z(θ −sω)(g( ,·),A ( ))+z(θ −sω)∥∇ ( )∥2. By he Young inequali y and (2.5) we ob ain e−z(θ −sω)( (ez(θ −ρ( )−sω) ( −ρ( ))),A ( )) ≤ν 6∥A ( )∥2+ce−2z(θ −sω)e2z(θ −ρ( )−sω)∥ ( −ρ( ))∥2, and e−z(θ −sω)(g( ,·),A ( )) ≤ν 6∥A ( )∥2+ce−2z(θ −sω)∥g( )∥2. I ollows om (2.8) and he Gaglia do-Ni enbe g inequali y ha −ez(θ −s)b( ( ), ( ),A ( ))≤ez(θ −s)∥ ( )∥L4(O;R2)∥∇ ( )∥L4(O;R4)∥A ( )∥ ≤ez(θ −s)∥ ( )∥1 2∥∇ ( )∥∥A ( )∥3 2 ≤ acν6∥A ( )∥2+ce4z(θ −sω)∥ ( )∥2∥∇ ( )∥4. Hence we ha e d d ∥∇ ( )∥2+ν∥A ( )∥2≤ce−2z(θ −sω)e2z(θ −ρ( )−sω)∥ ( −ρ( ))∥2 +ce−2z(θ −sω)∥g( )∥2+ce4z(θ −sω)∥ ( )∥2∥∇ ( )∥4.(3.17) Using he uni o m G onwall inequali y o (3.17) we ob ain o all ξ∈[−2ϱ−2,0], ∥∇ (s+ξ)∥2 ≤ceRs+ξ s+ξ−1e4z(θ −sω)∥ ( )∥2∥∇ ( )∥2d Zs+ξ s+ξ−1 e−2z(θ −sω)e2z(θ −ρ( )−sω)∥ ( −ρ( ))∥2d +ceRs+ξ s+ξ−1e4z(θ −sω)∥ ( )∥2∥∇ ( )∥2d Zs+ξ s+ξ−1 (e−2z(θ −sω)∥g( )∥2+∥∇ ( )∥2)d ≤C(ω)eC(ω)Rs s−2ϱ−3∥ ( )∥2∥∇ ( )∥2d Zs s−2ϱ−3 (∥ ( −ρ( ))∥2+∥g( )∥2+∥∇ ( )∥2)d , which, along wi h (2.1), implies ∥∇u(s+ξ)∥2 ≤C(ω)eC(ω)Rs s−2ϱ−3∥u( )∥2∥∇u( )∥2d Zs s−2ϱ−3 (∥u( −ρ( ))∥2+∥g( )∥2+∥∇u( )∥2)d . To show ha ∥∇u(s+ξ)∥2is bounded o all s≤τ, we need p o e Rs s−2ϱ−3∥∇ ( )∥2d is bounded. To his end, in eg a ing (3.10) o e [s−2ϱ−3,s] by (2.1) we ob ain sup s≤τZs s−2ϱ−3 ∥∇u( )∥2d ≤C(ω)sup s≤τ ∥u(s−2ϱ−3)∥2 +C(ω)sup s≤τZs s−2ϱ−3 (∥u( −ρ( ))∥2+∥u( )∥2+∥g( )∥2)d . RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL 1154 STOCHASTIC DELAY NAVIER-STOKES EQUATIONS 3.3. Exis ence, uniqueness and backwa d compac ness o pullback an- dom a ac o s. We now es ablish he exis ence, uniqueness and backwa d com- pac ness o pullback andom a ac o s o (1.1). Fo he pu pose o his subsec ion, we show ha he Φ in (2.10) has a pullback andom abso bing se . Theo em 3.1. Suppose ha (D) and (F) hold, and g∈L2 loc(R;(L2(O))2)is backwa d empe ed and backwa d ail-small. Then we ob ain he ollowing esul s: (i) Φ has a D-pullback andom abso bing se Kd={Kd(τ,ω) : τ∈R,ω ∈Ω}∈ D, de- ined by Kd(τ,ω)={ϕ∈CH:∥ϕ∥2 CH≤cecϱ(1+Rd(τ,ω)) sup ξ∈[−3ϱ−3,0] e2z(θξω)}.(3.50) (ii) Φ has a B-pullback abso bing se Kb={Kb(τ,ω):τ∈R,ω ∈Ω}∈B, de ined by Kb(τ,ω)={ϕ∈CH:∥ϕ∥2 CH≤cecϱ(1+Rb(τ,ω)) sup ξ∈[−3ϱ−3,0] e2z(θξω)},(3.51) whe e Rd(τ,ω)and Rb(τ,ω)a e gi en in (3.7)and (3.9), espec i ely. P oo . The p oo is simila o [43, Lemma 3.3], and so is omi ed. We ema k ha he measu abili y o he B-pullback abso bing se Kbis unknown, bu we can show ha he B-pullback a ac o is measu able (see Theo em 3.4). We i s p o e he B-pullback asymp o ic compac ness o Φ in (2.10). Theo em 3.2. Suppose ha (D) and (F) hold, and g∈L2 loc(R;(L2(O))2)is backwa d empe ed and backwa d ail-small. Then Φin (2.10)is backwa d B- pullback asymp o ically compac , ha is, o each τ∈R,ω∈Ωand B∈B, he se- quence {Φ( n,sn− n,θ− nω)ψn}n∈Nis p e-compac in CH, whene e n→+∞,sn≤τ and ψn∈B(sn− n,θ− nω). P oo . Based on he Ascoli-A zel`a heo em, he p oo is spli in o wo s eps. S ep 1. Fo each ξ∈[−ϱ,0], we p o e {(Φ( n,sn− n,θ− nω)ψn)(ξ)}n∈Nhas a con e gen subsequence in H. Since n→+∞as n→+∞, we assume ha n≥Tb o all n∈N. F om (3.8), we ob ain {(Φ( n,sn− n,θ− nω)ψn)(ξ)}n∈Nis bounded in H, and so {(Φ( n,sn− n,θ− n)ψn)(ξ)}n∈Nhas a weakly con e gen subsequence (no elabelled), ha is, he e exis s a ˜ ∈Hsuch ha (Φ( n,sn− n,θ− nω)ψn)(ξ)= u(sn+ξ,sn− n,θ−snω,ψn)→˜uweakly in H. (3.52) We now show ha he weak con e gence o (3.52) is s ong. Since ˜u∈H, o any ε>0 he e exis s a ˜ K:= ˜ K(ε)>0 such ha Z|x|≥ ˜ K |˜u|2dx < ε 5.(3.53) Le ¯ K=max{K, ˜ K}, whe e Kis gi en in Lemma 3.4. F om (3.35), we ha e Z|x|≥ ¯ K |u(sn+ξ,sn− n,θ−snω,ψn)|2dx< ε 5.(3.54) RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL QIANGHENG ZHANG, TOM´ AS CARABALLO, AND SHUANG YANG 1155 By (3.16), {(Φ( n,sn− n,θ− nω)ψn)(ξ)}n∈Nis bounded in V, and so i is bounded in H1(O¯ K), whe e O¯ K={x:|x|<¯ K}. Hence {(Φ( n,sn− n,θ− nω)ψn)(ξ)}n∈Nis p e- compac in L2(O¯ K), ha is, he e exis s a N > 0 such ha o all n≥N ∥u(sn+ξ,sn− n,θ−snω,ψn)−˜u∥2 L2(O¯ K)<ε 5.(3.55) I ollows om (3.53)-(3.55) ha ∥u(sn+ξ,sn− n,θ−snω,ψn)−˜u∥2 =Z|k|≥ ¯ K | (sn+ξ,sn− n,θ−snω,ψn)−˜u|2dx +∥u(sn+ξ,sn− n,θ−snω,ψn)−˜u∥2 L2(O¯ K) ≤2Z|k|≥ ¯ K |u(sn+ξ,sn− n,θ−snω,ψn)|2dx+2Z|k|≥ ¯ K |˜u|2dx +∥u(sn+ξ,sn− n,θ−snω,ψn)−˜u∥2 L2(O¯ K)<ε, which implies he weak con e gence o (3.52) is s ong con e gence. The p oo o S ep 1is comple e. S ep 2. We p o e {Φ( n,sn− n,θ− nω)ψn}n∈Nin CHis equi-con inuous om [−ϱ,0] o H. Fo each ξ1,ξ2∈[−ϱ,0] wi h ξ1< ξ2, by (3.21) we deduce |(Φ( n,sn− n,θ− nω)ψn)(ξ1)−(Φ( n,sn− n,θ− nω)ψn)(ξ2)∥ =∥u(sn+ξ1,sn− n,θ−snω,ψn)−u(sn+ξ2,sn− n,θ−snω,ψn)∥ ≤ez(θξ1ω)∥ (sn+ξ1,sn− n,θ−snω,ϕn)− (sn+ξ2,sn− n,θ−snω,ϕn)∥ +|ez(θξ1ω)−ez(θξ2ω)|∥ (sn+ξ2,sn− n,θ−snω,ϕn)∥ ≤C(ω)Zsn+ξ2 sn+ξ1 ∥∂ ∂ ( ,sn− n,θ−snω,ϕn)∥d +C(ω)ecϱ(1+Rb(τ,ω))|ez(θξ1ω)−ez(θξ2ω)| ≤C(ω)Zsn sn−ϱ ∥∂ ∂ ( ,sn− n,θ−snω,ϕn)∥2d 1 2 |ξ1−ξ2|1 2 +C(ω)ecϱ(1+Rb(τ,ω))|ez(θξ1ω)−ez(θξ2ω)| ≤C(ω)¯ R3 b(τ,ω)eC(ω)¯ R2 b(τ,ω)|ξ1−ξ2|1 2 +C(ω)ecϱ(1+Rb(τ,ω))|ez(θξ1ω)−ez(θξ2ω)|, which implies ha {Φ( n,sn− n,θ− nω)ψn}n∈Nis equi-con inuous. The p oo o S ep 1is comple e. We ob ain ha all condi ions o he Ascoli-A zel`a heo em a e ul illed, and so he p oo is comple e. We hen show he D-pullback asymp o ic compac ness o Φ in (2.10). Theo em 3.3. Suppose ha (D) and (F) hold, and g∈L2 loc(R;(L2(O))2)is empe ed and ail-small. Then Φin (2.10)is D-pullback asymp o ically compac , ha is, o each τ∈R,ω∈Ωand D∈D, he sequence {Φ( n,τ − n,θ− nω)ψn}n∈Nis p e-compac in CH, whene e n→+∞and ψn∈D(τ− n,θ− nω). RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL 1156 STOCHASTIC DELAY NAVIER-STOKES EQUATIONS P oo . The asymp o ic compac ness has been p o ed o he amily Bin Theo em 3.2, his esul also holds o he amily D. The p oo is simila o ha o Theo em 3.2, and we omi he de ails. Now, we ob ain he main esul o his sec ion. Theo em 3.4. Suppose ha (D) and (F) hold, and g∈L2 loc(R;(L2(O))2)is backwa d empe ed and backwa d ail-small. Then we ob ain he ollowing esul s: (i) Φ has a unique D-pullback andom a ac o Ad={Ad(τ,ω):τ∈R,ω ∈Ω}∈D, de ined by Ad(τ,ω)= T≥0[ ≥T Φ( ,τ − ,θ− ω)Kd(τ− ,θ− ω). (ii) Φ has a unique B-pullback a ac o Ab={Ab(τ,ω):τ∈R,ω ∈Ω}∈B, de ined by Ab(τ,ω)= T≥0[ ≥T Φ( ,τ − ,θ− ω)Kb(τ− ,θ− ω). In addi ion, Abis backwa d compac , ha is, Ss≤τAb(s,ω)is compac in H. (iii) Ad=Ab, and so Abis measu able and Adis backwa d compac . P oo . The p oo is simila o [43, Theo em 3.10], and so is omi ed. 4. Uppe semicon inui y o pullback andom a ac o In his sec ion, we conside he uppe semicon inui y o he pullback andom a ac- o as he delay ime ends o ze o. Fo his pu pose, we in oduce he limi equa ion o (1.1):              d¯u−(ν∆¯u−(¯u·∇)¯u−∇p)d =( (¯u( ))+g( ,x))d + ¯u◦dW, x∈O, > τ, ∇· ¯u= 0, x∈O, >τ, ¯u=0, x ∈∂O, > τ, ¯u(τ):= ¯ ψ, τ ∈R. (4.1) Using (2.1) o (4.1), we ob ain                  ∂¯ ∂ −ν∆¯ +ez(θ ω)(¯ ·∇)¯ +e−z(θ ω)∇p =e−z(θ ω)( (ez(θ ω)¯ ( ))+g( ,x))+z(θ ω)¯ , x ∈O, > τ, ∇· ¯ = 0, x∈O, >τ, ¯ = 0, x ∈∂O, > τ, ¯ (τ) := ¯ ϕ, τ ∈R. (4.2) By he same me hod as in Sec ion 3, we ob ain ha ¯ Φ gene a ed by (4.2) has a unique D0-pullback andom a ac o A0={A0(τ,ω) :τ∈R,ω ∈Ω}∈ D0, and a D0-pullback andom abso bing se K0={K0(τ,ω):τ∈R,ω ∈Ω}∈D0, whe e D0={D0={D0(τ,ω):τ∈R,ω ∈Ω}: lim →+∞e−κ ∥D0(τ− ,θ− ω)∥2=0}, RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL QIANGHENG ZHANG, TOM´ AS CARABALLO, AND SHUANG YANG 1157 and K0(τ,ω)={ϕ∈CH:∥ϕ∥2 CH≤cecϱ0(1+Rd(τ,ω)) sup ξ∈[−3ϱ0−3,0] e2z(θξω)}.(4.3) We ew i e Kdand Ad(Kdis gi en by (3.50) and Adis gi en by Theo em 3.4) o Kϱ and Aϱ. Since he delay ime ϱ∈(0,ϱ0], by (3.50) and (4.3) we ha e limsup ϱ→0 ∥Kϱ(τ,ω)∥2 CH=∥K0(τ,ω)∥2,∀τ∈R, ω ∈Ω.(4.4) We now conside he poin wise con e gence o Aϱ: Lemma 4.1. Suppose ha {ϕn}n∈N⊂ Aϱn(τ,ω)wi h ϱn→0, hen he e exis a subse- quence {ϕnk}k∈No {ϕn}n∈Nand ϕ∈Hsuch ha lim k→+∞sup ξ∈[−ϱnk,0] ∥ϕnk(ξ)−ϕ∥=0.(4.5) P oo . The p oo is simila o [42, Lemma 5.2], and so is omi ed. Nex , we conside he con e gence o solu ions o he delay sys em o hose o he non-delay one. Lemma 4.2. Suppose ha ϕϱ∈CHand ϕ0∈Hsa is y lim ϱ→0sup ξ∈[−ϱ,0] ∥ϕϱ(ξ)−ϕ0∥=0,(4.6) hen he solu ion ϱo (2.3)and he solu ion 0o (4.2)associa ed wi h he ini ial da a ϕϱand ϕ0sa is y lim ϱ→0sup ξ∈[−ϱ,0] ∥ ϱ( +τ+ξ,τ,θ−τω,ϕϱ)− 0( +τ,τ,θ−τω,ϕ0)∥=0,(4.7) o all ≥0,τ∈Rand ω∈Ω. Mo eo e , we ha e lim ϱ→0sup ξ∈[−ϱ,0] ∥uϱ( +τ+ξ,τ,θ−τω,ψϱ)−u0( +τ,τ,θ−τω,ψ0)∥=0.(4.8) P oo . Fo each τ∈R, we de ine ¯ Vϱ( )= ϱ( +ξ,τ,θ−τω,ϕϱ)− 0( ,τ,θ−τω,ϕ0),∀ ≥τ. F om (2.3) and (4.2), we ob ain ∂¯ Vϱ( +τ) ∂ −ν∆¯ Vϱ( +τ)+ez(θ +ξω)( ϱ( +τ+ξ)·∇) ϱ( +τ+ξ) −ez(θ ω)( 0( +τ)·∇) 0( +τ)+e−z(θ +ξω)∇pϱ−e−z(θ ω)∇p0 =e−z(θ +ξω)( (ez(θ +ξ−ρ( +τ+ξ)ω) ϱ( +τ+ξ−ρ( +τ+ξ)))+g( +τ+ξ,x)) −e−z(θ ω)( (ez(θ −ρ( +τ)ω) 0( +τ))+g( +τ,x)) +z(θ +ξω) ϱ( +τ+ξ)−z(θ ω) 0( +τ). Mul iplying he abo e equali y by ¯ Vϱ( +τ), and hen in eg a ing his esul o e O, we deduce 1 2 d d ∥¯ Vϱ( +τ)∥2+ν∥∇ ¯ Vϱ( +τ)∥2 RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL 1158 STOCHASTIC DELAY NAVIER-STOKES EQUATIONS +(ez(θ +ξω)( ϱ( +τ+ξ)·∇) ϱ( +τ+ξ),¯ Vϱ( +τ)) −(ez(θ ω)( 0( +τ)·∇) 0( +τ),¯ Vϱ( +τ)) =(e−z(θ +ξω) (ez(θ +ξ−ρ( +τ+ξ)ω) ϱ( +τ+ξ−ρ( +τ+ξ))),¯ Vϱ( +τ)) −(e−z(θ ω) (ez(θ −ρ( +τ)ω) 0( +τ)),¯ Vϱ( +τ)) +(e−z(θ +ξω)g( +τ+ξ,·)−e−z(θ ω)g( +τ,·),¯ Vϱ( +τ)) +(z(θ +ξω) ϱ( +τ+ξ)−z(θ ω) 0( +τ),¯ Vϱ( +τ)).(4.9) I ollows om (2.8) and he Gaglia do-Ni enbe g inequali y ha −(ez(θ +ξω)( ϱ( +τ+ξ)·∇) ϱ( +τ+ξ),¯ Vϱ( +τ)) +(ez(θ ω)( 0( +τ)·∇) 0( +τ),¯ Vϱ( +τ)) =−ez(θ +ξω)(( ϱ( +τ+ξ)·∇) ϱ( +τ+ξ),¯ Vϱ( +τ)) −(( 0( +τ)·∇) 0( +τ),¯ Vϱ( +τ)) −(ez(θ +ξω)−ez(θ ω))(( 0( +τ)·∇) 0( +τ),¯ Vϱ( +τ)) =−ez(θ +ξω)b(¯ Vϱ( +τ), 0( +τ),¯ Vϱ( +τ)) +(ez(θ +ξω)−ez(θ ω))b( 0( +τ),¯ Vϱ( +τ), 0( +τ)) ≤ez(θ +ξω)∥¯ Vϱ( +τ)∥2 L4∥∇ 0( +τ)∥ +|ez(θ +ξω)−ez(θ ω)|∥ 0( +τ)∥2 L4∥∇ ¯ Vϱ( +τ)∥ ≤ez(θ +ξω)∥¯ Vϱ( +τ)∥∥∇ ¯ Vϱ( +τ)∥∥∇ 0( +τ)∥ +|ez(θ +ξω)−ez(θ ω)|∥ 0( +τ)∥∥∇ 0( +τ)∥∥∇ ¯ Vϱ( +τ)∥ ≤ν 4∥∇ ¯ Vϱ( +τ)∥2+cez(θ +ξω)∥¯ Vϱ( +τ)∥2∥∇ 0( +τ)∥2 +c|ez(θ +ξω)−ez(θ ω)|2∥ 0( +τ)∥2∥∇ 0( +τ)∥2.(4.10) By (2.5) we de i e (e−z(θ +ξω) (ez(θ +ξ−ρ( +τ+ξ)ω) ϱ( +τ+ξ−ρ( +τ+ξ))),¯ Vϱ( +τ)) −(e−z(θ ω) (ez(θ −ρ( +τ)ω) 0( +τ)),¯ Vϱ( +τ)) ≤ν 4∥∇ ¯ Vϱ( +τ)∥2 +ce−2z(θ +ξω)e2z(θ +ξ−ρ( +τ+ξ)ω)∥ ϱ( +τ+ξ−ρ( +τ+ξ))− 0( +τ)∥2 +c(ez(θ +ξ−ρ( +τ+ξ)ω)−ez(θ −ρ( +τ)ω))2∥ 0( +τ)∥2 +c(e−z(θ +ξω)−e−z(θ ω))2e2z(θ −ρ( +τ)ω)∥ 0( +τ)∥2.(4.11) The Young inequali y implies (e−z(θ +ξω)g( +τ+ξ,·)−e−z(θ ω)g( +τ,·),¯ Vϱ( +τ)) +(z(θ +ξω) ϱ( +τ+ξ)−z(θ ω) 0( +τ),¯ Vϱ( +τ)) ≤ν 4∥∇ ¯ Vϱ( +τ)∥2+ce−2z(θ +ξω)∥g( +τ+ξ)−g( +τ)∥2 +c(e−z(θ +ξω)−e−z(θ ω))2∥g( +τ)∥2+|z(θ +ξω)|∥ ¯ Vϱ( +τ)∥2 +c(z(θ +ξω)−z(θ ω))2∥ 0( +τ)∥2.(4.12) RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL QIANGHENG ZHANG, TOM´ AS CARABALLO, AND SHUANG YANG 1159 Subs i u ing (4.10)-(4.12) in o (4.9), and hen in eg a ing his esul o e [−ξ, ] wi h ∈[−ξ,T] and T > ϱ0we show ∥¯ Vϱ( +τ)∥2≤ ∥ ¯ Vϱ(−ξ+τ)∥2+C(ω)Z −ξ (1+∥∇ 0( +τ)∥2)∥¯ Vϱ( +τ)∥2d +C(ω)Z −ξ ∥ ϱ( +τ+ξ−ρ( +τ+ξ))− 0( +τ)∥2d +C(ω)ZT 0 (ez(θ +ξω)−ez(θ ω))2∥ 0( +τ)∥2∥∇ 0( +τ)∥2d +C(ω)ZT 0 (ez(θ +ξ−ρ( +τ+ξ)ω)−ez(θ −ρ( +τ)ω))2∥ 0( +τ)∥2d +C(ω)ZT 0 ((e−z(θ +ξω)−e−z(θ ω))2+(z(θ +ξω)−z(θ ω))2)∥ 0( +τ)∥2d +C(ω)ZT 0 ∥g( +τ+ξ)−g( +τ)∥2d +C(ω)ZT 0 (e−z(θ +ξω)−e−z(θ ω))2∥g( +τ)∥2d . (4.13) We now mainly ea he second line o (4.13). Le s=y( )= +ξ−ρ( +ξ) o any ∈Rand ixed ξ∈[−ϱ,0]. Since y′( )≥1−ρ∗>0, i has an in e se unc ion such ha =y−1(s) o any s∈R. Then, Z −ξ ∥ ϱ( +τ+ξ−ρ( +τ+ξ))− 0( +τ)∥2d = Zy−1(τ) τ−ξ +Z +τ y−1(τ)!∥ ϱ( +ξ−ρ( +ξ))− 0( )∥2d =Zy−1(τ) τ−ξ ∥ ϱ( +ξ−ρ( +ξ))− 0( )∥2d +Z +τ−ρ( +τ+ξ) τ−ξ ∥ ϱ( +ξ)− 0(y−1( +ξ))∥2 1−d d ρ(y−1( +ξ)+ξ)d ≤2Zy−1(τ) τ−ξ ∥ ϱ( +ξ−ρ( +ξ))−ϕ0∥2d +2Zy−1(τ) τ−ξ ∥ 0( )−ϕ0∥2d +2 1−ρ∗Zτ+ τ−ξ ∥ ϱ( +ξ)− 0( )∥2d +2 1−ρ∗Zτ+ τ−ξ ∥ 0(y−1( +ξ))− 0( )∥2d ≤2 1−ρ∗Zτ τ−ρ(τ) ∥ ϱ( )−ϕ0∥2d +2Zy−1(τ) τ−ξ ∥ 0( )−ϕ0∥2d +2 1−ρ∗Zτ+ τ−ξ ∥ ϱ( +ξ)− 0( )∥2d +2 1−ρ∗Zτ+ τ−ξ ∥ 0(y−1( +ξ))− 0( )∥2d . RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL 1160 STOCHASTIC DELAY NAVIER-STOKES EQUATIONS No e ha Zτ τ−ρ(τ) ∥ ϱ( )−ϕ0∥2d ≤cϱ sup ξ∈[−ϱ,0] ∥ϕϱ(ξ)−ϕ0∥2, and Zτ+ τ−ξ ∥ ϱ( +ξ)− 0( )∥2d =Z −ξ ∥¯ Vϱ( +τ)∥2d . Then we imply Z −ξ ∥ ϱ( +τ+ξ−ρ( +τ+ξ))− 0( +τ)∥2d ≤cϱ sup ξ∈[−ϱ,0] ∥ϕϱ(ξ)−ϕ0∥2+cZy−1(τ) τ−ξ ∥ 0( )−ϕ0∥2d +cZ −ξ ∥¯ Vϱ( +τ)∥2d +cZτ+ τ−ξ ∥ 0(y−1( +ξ))− 0( )∥2d . (4.14) By he same me hod as in Lemma 3.1 and Lemma 3.2 we ob ain ha ∥ 0( +τ)∥2and ∥∇ 0( +τ)∥2a e bounded when ∈[0,T ]. Then, om (4.13) and (4.14) we de i e ∥¯ Vϱ( +τ)∥2 ≤∥ ¯ Vϱ(−ξ+τ)∥2+C(ω)Z −ξ ∥¯ Vϱ( +τ)∥2d +C(ω) sup ξ∈[−ϱ,0] ∥ϕϱ(ξ)−ϕ0∥2 +C(ω)Zy−1(τ) τ−ξ ∥ 0( )−ϕ0∥2d +C(ω)Zτ+ τ−ξ ∥ 0(y−1( +ξ))− 0( )∥2d +C(ω)ZT 0 ((ez(θ +ξω)−ez(θ ω))2+(ez(θ +ξ−ρ( +τ+ξ)ω)−ez(θ −ρ( +τ)ω))2)d +C(ω)ZT 0 ((e−z(θ +ξω)−e−z(θ ω))2+(z(θ +ξω)−z(θ ω))2)d +C(ω)ZT 0 ∥g( +τ+ξ)−g( +τ)∥2d +C(ω)ZT 0 (e−z(θ +ξω)−e−z(θ ω))2∥g( +τ)∥2d . (4.15) By (4.6) and he con inui y o 0a τwe ob ain ∥¯ Vϱ ξ(−ξ+τ)∥2=∥ ϱ(τ,τ,θ−τω,ϕϱ)− 0(−ξ+τ,τ,θ−τω,ϕ0)∥2 ≤2∥ϕϱ(0)−ϕ0∥2+2∥ϕ0− 0(−ξ+τ,τ,θ−τω,ϕ0)∥2 ≤2 sup ξ∈[−ϱ,0] ∥ϕϱ(ξ)−ϕ0∥2+2∥ϕ0− 0(−ξ+τ,τ,θ−τω,ϕ0)∥2→0 as ϱ→0.(4.16) By he con inui y o 0a τwe show C(ω)Zy−1(τ) τ−ξ ∥ 0( )−ϕ0∥2d +C(ω)Zτ+ τ−ξ ∥ 0(y−1( +ξ))− 0( )∥2d →0 (4.17) RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL QIANGHENG ZHANG, TOM´ AS CARABALLO, AND SHUANG YANG 1161 as ϱ→0, whe e we use y−1(τ)≤τ+2ϱ. Using he con inui y o →z(θ ω) yields C(ω)ZT 0 ((ez(θ +ξω)−ez(θ ω))2+(ez(θ +ξ−ρ( +τ+ξ)ω)−ez(θ −ρ( +τ)ω))2)d +C(ω)ZT 0 ((e−z(θ +ξω)−e−z(θ ω))2+(z(θ +ξω)−z(θ ω))2)d →0 as ϱ→0.(4.18) F om g∈L2 loc(R,(L2(O))2), we ha e C(ω)ZT 0 ∥g( +τ+ξ)−g( +τ)∥2d +C(ω)ZT 0 (e−z(θ +ξω)−e−z(θ ω))2∥g( +τ)∥2d →0 as ϱ→0.(4.19) Inse ing (4.16)-(4.19) o (4.15), o any ε>0, he e exis s a ¯ϱ∈(0,ϱ0] such ha o all ϱ< ¯ϱ, ∥¯ Vϱ( +τ)∥2≤C(ω)ε+C(ω)Z −ξ ∥¯ Vϱ( +τ)∥2d . (4.20) Using he G onwall inequali y (see [13, page 167]) o (4.20), we ob ain o all ϱ< ¯ϱand ∈[−ξ,T] wi h ξ∈[−ϱ,0], ∥¯ Vϱ( +τ)∥2<C(ω)eC(ω)Tε. (4.21) I ∈[0,−ξ], we ha e τ+ξ≤ +τ+ξ≤τ. Hence we deduce ∥ ϱ( +τ+ξ)− 0( +τ)∥2≤2∥ ϱ( +τ+ξ)−ϕ0∥2+2∥ 0( +τ)−ϕ0∥2 ≤2 sup ξ∈[−ϱ,0] ∥ϕϱ(ξ)−ϕ0∥2 V+2∥ 0( +τ)−ϕ0∥2→0,as ϱ→0.(4.22) I ollows om (4.21) and (4.22) ha lim ϱ→0∥¯ Vϱ( +τ)∥2=0,∀ ∈[0,T ], which implies ha (4.7) holds. By (2.1) we ha e ∥uϱ( +τ+ξ,τ,θ−τω,ψϱ)−u0( +τ,τ,θ−τω,ψ0)∥ ≤ez(θ +ξω)∥ ϱ( +τ+ξ,τ,θ−τω,ψϱ)− 0( +τ,τ,θ−τω,ψ0)∥ +|ez(θ +ξω)−ez(θ ω)|∥u0( +τ,τ,θ−τω,ψ0)∥, which, along wi h (5.7) and he con inui y o z(θ·ω), implies ha (4.8) holds. The p oo is comple e. I ollows om (4.4), Lemma 4.1 and Lemma 4.2 ha all condi ions o [36, Theo em 2.1] a e sa is ied. Then we ob ain he main esul o his sec ion: Theo em 4.1. Suppose ha (D) and (F) hold, and g∈L2 loc(R;(L2(O))2)is backwa d empe ed and backwa d ail-small. Then we ha e lim ϱ→0dis ϱ(Aϱ(τ,ω),A0(τ,ω))= 0, o all τ∈R, ω ∈Ω. RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL 1162 STOCHASTIC DELAY NAVIER-STOKES EQUATIONS 5. Asymp o ic au onomy o pullback andom a ac o Le ρ( )=ϱin (1.1) o all ∈R, hen we ha e              du−(ν∆u−(u·∇)u−∇p)d =( (u( −ϱ))+g( ,x))d +u◦dW, ∇·u=0, x ∈O, > τ, u=0, x ∈∂O, > τ, u(τ+ξ)=uτ(ξ):= ψ(ξ), ξ ∈[−ϱ,0], τ ∈R. (5.1) Using (2.1) o (5.1) we ob ain he ollowing andom equa ion:                  ∂ ∂ −ν∆ +ez(θ ω)( ·∇) +e−z(θ ω)∇p =e−z(θ ω)( (ez(θ −ϱω) ( −ϱ))+g( ,x))+z(θ ω) , x ∈ O, >τ, ∇· =0, x ∈O, > τ, =0, x ∈∂O, > τ, (τ+ξ)= τ(ξ):= ϕ(ξ), ξ ∈[−ϱ,0], τ ∈R. (5.2) Using he same me hod as in Sec ion 3, we ob ain ha he non-au onomous andom dynamical sys ems Φ gene a ed by (5.1) ha e a unique backwa d compac D-pullback andom a ac o Aϱ={Aϱ(τ,ω):τ∈R,ω ∈Ω}, and a D-pullback abso bing se K= {K(τ,ω): τ∈R,ω ∈Ω}, de ined by K(τ,ω)={ϕ∈CH:∥ϕ∥2 CH≤cecϱ(1+Rb(τ,ω)) sup ξ∈[−3ϱ−3,0] e2z(θξω)},(5.3) whe e Rb(τ,ω) is gi en by (3.9). We now in oduce he au onomous e sion o (5.1):              d˜u−(ν∆˜u−(˜u·∇)˜u−∇p)d =( (˜u( −ϱ))+g∞(x))d + ˜u◦dW, ∇· ˜u= 0, x∈O, >0, ˜u=0, x ∈∂O, > 0, ˜u(0+ξ) = ˜u0(ξ):= ˜ ψ(ξ), ξ ∈[−ϱ,0], (5.4) whe e he o cing g∞sa is ies lim τ→−∞Zτ −∞ ∥g( )−g∞∥2d =0.(5.5) Using (2.1) o (5.4), we ob ain                  ∂˜ ∂ −ν∆˜ +ez(θ ω)( ·∇) +e−z(θ ω)∇˜p =e−z(θ ω)( (ez(θ −ϱω)˜ ( −ϱ))+g∞(x))+z(θ ω)˜ , x∈O, > τ, ∇· ˜ = 0, x∈O, >τ, ˜ = 0, x ∈∂O, > τ, ˜ (0+ξ)= ˜ 0(ξ):= ˜ ϕ(ξ), ξ ∈[−ϱ,0], τ ∈R. (5.6) Simila o Theo em 3.4, we ob ain ha he au onomous andom dynamical sys em Φ∞ associa ed wi h (5.4) has a unique D∞- andom a ac o A∞={A∞(ω):ω∈Ω} ∈D∞ wi h D∞being he collec ion o all empe ed amilies in CH, mo e p ecisely, D∞={D∞={D∞(ω):ω∈Ω}: lim →+∞e−κ ∥D∞(θ− ω)∥2 CH=0}.(5.7) RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL QIANGHENG ZHANG, TOM´ AS CARABALLO, AND SHUANG YANG 1163 In his sec ion, we conside he asymp o ic au onomy o Aϱ: lim τ→−∞dis CH(Aϱ(τ,ω),A∞(ω))=0,∀ω∈Ω.(5.8) Le Kbu ={Kbu(ω):ω∈Ω}wi h Kbu(ω)=Ss≤0K(s,ω) o all ω∈Ω. We now p o e Kbu ∈ D∞. Le δ1=min{¯η 6,κ 8}, by (2.2) and (3.3) he e exis s a ˜ T:= ˜ T(δ1,ω)>0 such ha e−2z(θ ω)≤eδ1| |,Z 0 (η(θ ω)−¯η)d  ≤δ1| |, o all | |≥ ˜ T. Hence, we ob ain o all ≥˜ Tand ≤0 eR 0η(θl− ω)dl+2|z(θ − ω)|=eR − − η(θlω)dl+2|z(θ − ω)| ≤eR − 0(η(θlω)−¯η)dl+¯γ( − )−R− 0(η(θlω)−¯η)dl+¯η +2|z(θ − ω)| ≤e|R − 0(η(θlω)−¯η)dl|+|R− 0(η(θlω)−¯η)dl|+¯η +δ1( − ) ≤e3δ1 e(¯η−2δ1) ≤e3δ1 e2δ1 . By (3.9) and (5.3) we imply Kis closed and inc easing. Then we ha e e−κ ∥Kbu(θ− ω)∥2 CH =e−κ ∥[ s≤0 K(s,θ− ω)∥2 CH=e−κ ∥K(0,θ− ω)∥2 CH ≤ce−κ eνλϱ(1+Rb(0,θ− ω)) sup ξ∈[−3ϱ−3,0] e2z(θ− +ξω) =ce−(κ−2δ1) e(νλ+2δ1)ϱ(1+sup s≤0 Rd(s,θ− ω)) sup ξ∈[−3ϱ−3,0] e2z(θ− +ξω) ≤ce−(κ−2δ1) e(νλ+2δ1)ϱ(1+sup s≤0Z0 −∞ eR 0η(θl− ω)dle−2z(θ − ω)∥g( +s)∥2d ) ≤ce−(κ−5δ1) e(νλ+2δ1)ϱ(1+sup s≤0Z0 −∞ e2δ1 ∥g( +s)∥2d )→0,as →+∞. Hence we ha e Kbu ∈D∞. Nex , we p o e he con e gence o solu ions o he non- au onomous sys em o hose o he au onomous one. Lemma 5.1. Suppose ha τ,˜ 0∈CHsa is y lim τ→−∞∥ τ−˜ 0∥2 CH=0,(5.9) hen we ha e lim τ→−∞∥u +τ(·,τ,θ−τω,uτ)−˜u (·,ω, ˜u0)∥2 CH=0,(5.10) o all ≥0and ω∈Ω. P oo . Fo each τ∈R, le ˜ Vτ( )= ( +τ,τ,θ−τω, τ)−˜ ( ,ω,˜ 0),∀ ≥ −ϱ. RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL RJ+p466N wh o7OTAxeHNE kl XQJ6BsgJl3zskmMX dqykiwc3 xnmdadVIa0udgdaQiPTwB3DDx0XF8NVCK/CjwH/AHjixQjh5EVJGqheRRAnGUX8I6NkHIQYjxzZL