Initial-boundary-value problems for quasilinear degenerate hyperbolic equations with damping. Neumann problem

We study the behavior of the total mass of the solution of Neumann problem for a broad class of degenerate parabolic equations with damping in spaces with noncompact boundary. New critical indices for the investigated problem are determined.

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Date:2006
Main Authors: Tedeev, A. F., Тедеев, А. Ф.
Format: Article
Language:Russian
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Published: Institute of Mathematics, NAS of Ukraine 2006
Online Access:https://umj.imath.kiev.ua/index.php/umj/article/view/3451
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Journal Title:Ukrains’kyi Matematychnyi Zhurnal
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Ukrains’kyi Matematychnyi Zhurnal
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author Tedeev, A. F.
Тедеев, А. Ф.
Тедеев, А. Ф.
author_facet Tedeev, A. F.
Тедеев, А. Ф.
Тедеев, А. Ф.
author_sort Tedeev, A. F.
baseUrl_str https://umj.imath.kiev.ua/index.php/umj/oai
collection OJS
datestamp_date 2020-03-18T19:54:47Z
description We study the behavior of the total mass of the solution of Neumann problem for a broad class of degenerate parabolic equations with damping in spaces with noncompact boundary. New critical indices for the investigated problem are determined.
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fulltext UDK 517.946 A. F. Tedeev (Yn-t prykl. matematyky y mexanyky NAN Ukrayn¥, Doneck) NAÇAL|NO-KRAEVÁE ZADAÇY DLQ KVAZYLYNEJNÁX VÁROÛDAGWYXSQ PARABOLYÇESKYX URAVNENYJ S DEMPFYROVANYEM. ZADAÇA NEJMANA* We investigate the behaviour of the total mass of a solution of the Neumann problem for a wide class of degenerate parabolic equations with damping in a space with a noncompact boundary. We find new critical indexes in the problem considered. DoslidΩu[t\sq povedinka total\no] masy rozv’qzku zadaçi Nejmana dlq ßyrokoho klasu vyrod- Ωenyx paraboliçnyx rivnqn\ z dempfiruvannqm u prostorax iz nekompaktnog meΩeg. Znajdeno novi krytyçni pokaznyky v doslidΩuvanij zadaçi. 1. Vvedenye. V dannoj rabote rassmatryvaetsq zadaça Nejmana ut = i N i m x q x u Du u a x Du i = − −∑ ∂ ∂ ( ) − 1 1 1λ ν( ) , ( x, t ) ∈ Ω × ( 0, ∞ ), (1.1) i N m x iu Du u n i = − −∑ 1 1 1λ = 0, ( x, t ) ∈ ∂ Ω × ( 0, ∞ ), (1.2) u ( x, 0 ) = u0 ( x ), x ∈ Ω, (1.3) hde Ω ⊂ R N, N ≥ 2, — neohranyçennaq oblast\ s dostatoçno hladkoj nekom- paktnoj hranycej, n = ( n i ) —7vneßnqq normal\ k ∂ Ω, Du = u ux xN1 , ,…( ). V dal\nejßem predpolahaem, çto a ( x ) y u0 ( x ) — neotrycatel\n¥e yzmerym¥e funkcyy, pryçem u0 ∈ L1 ( Ω ), t. e. u0 ymeet koneçnug massu. Krome toho, m + λ – 2 ≥ 0, λ > 0, 1 < q < λ + 1, ν q > m + λ – 1. (1.4) Budem predpolahat\ takΩe dopolnytel\n¥e uslovyq na dann¥e zadaçy. Uravne- nye ut = ∆u Du uq p− + δ , δ > 0, b¥lo vperv¥e yssledovano v rabote ·1‚ s cel\g yzuçenyq vlyqnyq çlena − Du q (yly, ynaçe, dempfyrovanyq) na problemu suwestvovanyq yly nesuwestvovanyq hlobal\n¥x po vremeny reßenyj zadaçy Dyryxle. Podrobn¥j analyz rezul\tatov v πtom napravlenyy moΩno najty v obzornoj rabote ·2‚. Otmetym takΩe nedavnyj cykl rabot ·3 – 6‚, hde ymegtsq dal\nejßye ss¥lky. Cel\g dannoj rabot¥ qvlqetsq naxoΩdenye uslovyj na q, pry kotor¥x massa reßenyq (1.1) – (1.3) u t( , ) ,⋅ 1 Ω ≡ u t L( , ) ( )⋅ 1 Ω stremytsq k nulg pry t → → ∞. Otmetym, çto esly a ( x ) ≡ 0 , to dlq poçty vsex t > 0 u t( , ) ,⋅ 1 Ω ≡ ≡ u0 1, Ω y, sledovatel\no, massa ne stremytsq k nulg pry t → ∞. Odnako, kak v¥qsnylos\, daΩe nalyçye syl\noho stoka, t. e. dempfyrovanyq, v (1.1) ne vseh- da harantyruet stremlenye k nulg mass¥ reßenyq (1.1) – (1.3). V sluçae a ( x ) ≡ ≡ const, Ω = R N (zadaça Koßy) zadaça (1.1), (1.3) yssledovalas\ v rabote ·7‚, hde dan otvet na vopros: pry kakyx uslovyqx na parametr¥ zadaçy massa reßenyq stremytsq k nulg? A ymenno, najden krytyçeskyj pokazatel\ q* = = N m N( ) ( )/+ − + +( ) +λ λ ν1 1 1 . ∏to oznaçaet, çto v sluçae q ≤ q* u t RN( , ) ,⋅ 1 → 0 pry t → ∞, a v sluçae q > q* u t RN( , ) ,⋅ 1 > c > 0 pry dosta- toçno bol\ßyx t > t0 . Krome toho, naprymer, esly supp u0 < ∞, to pry dosta- toçno bol\ßyx znaçenyqx t dokazan¥ sledugwye ocenky: *7 V¥polnena pry podderΩke INTAS (hrant 03-51-5007). © A. F. TEDEEV, 2006 272 ISSN 1027-3190. Ukr. mat. Ωurn., 2006, t. 58, # 2 NAÇAL|NO-KRAEVÁE ZADAÇY DLQ KVAZYLYNEJNÁX VÁROÛDAGWYXSQ … 273 u t RN( , ) ,⋅ 1 ≤ c t – A pry q < q *, (1.5) hde A = q q H N * − +( )ν 1 , H = ( )( ) ( )λ ν λ+ − − + −1 1 2q q m · y u t RN( , ) ,⋅ 1 ≤ C t q(ln ) − − 1 1ν pry q = q *. (1.6) Otmetym, çto zadaça (1.1) – (1.3) s a ( x ) ≡ 0 yzuçalas\ v rabotax ·8 – 11‚, hde b¥ly dan¥ toçn¥e ocenky u t( , ) ,⋅ ∞ Ω y heometryy nosytelq. Kombynyruq podxod¥, yzloΩenn¥e v πtyx rabotax y rabote ·7‚, m¥7ustanavlyvaem ocenky ty- pa (1.5) y (1.6), kotor¥e, kak πto budet vydno yz dal\nejßeho, suwestvenno zavy- sqt ot heometryy oblasty y povedenyq a ( x ) na beskoneçnosty. Dlq formuly- rovky osnovn¥x rezul\tatov y yx dokazatel\stv nam potrebuetsq rqd opredele- nyj y vspomohatel\n¥x predloΩenyj. Vsgdu v dal\nejßem çerez c budem obo- znaçat\ postoqnn¥e, zavysqwye lyß\ ot parametrov zadaçy y ne zavysqwye ot razmera oblasty Qt . 2. Vspomohatel\n¥e utverΩdenyq y formulyrovky osnovn¥x rezul\ta- tov. V¥delym klass¥ oblastej s nekompaktnoj hranycej, udovletvorqgwyx uslovyqm yzoperymetryçeskoho typa. Budem sçytat\, çto naçalo koordynat prynadleΩyt Ω. Pust\ l ( v ) = inf mes N Q− ∂( ){ }1 ∩ Ω , hde ynfymum beretsq po vsem otkr¥t¥m mnoΩestvam Q ⊂ Ω s lypßycevoj hranycej; mesN Q = v. Bu- dem hovoryt\, çto Ω prynadleΩyt klassu B1 ( g ), esly suwestvuet neub¥vag- waq neprer¥vnaq dlq vsex v > 0 funkcyq g ( v ) takaq, çto v v ( ) ( ) N N g − /1 ne ub¥va- et dlq vsex v > 0. Dalee, pust\ rk ( x ) = x xk1 2 2 1 2 +…+( ) / , 1 ≤ k ≤ N, y dlq zadan- noho ρ > 0 Ω ( ρ ) = Ω ∩ r xk ( ) <{ }ρ , V ( ρ ) = mesN Ω ( ρ ). Oboznaçym çerez R ob- ratnug k V ( ρ ) funkcyg. Budem hovoryt\, çto Ω prynadleΩyt klassu B2 ( g ), esly Ω ∈ B1 ( g ) y suwestvuet postoqnnaq c0 > 0 takaq, çto R ( v ) ≥ c g0 v v( ) (2.1) dlq vsex v > 0. Lehko vydet\, çto esly Ω ∈ B1 ( g ), to spravedlyvo obratnoe k (2.1) neravenstvo R ( v ) ≤ N g v v( ) (2.2) dlq vsex v > 0. Krome toho, yz (2.1) y (2.2) sleduet, çto 1 N g Vρ ρ( )( ) ≤ V ( ρ ) ≤ 1 0c g Vρ ρ( )( ) (2.3) dlq vsex ρ > 0. V svog oçered\, yz (2.3) v¥tekaet, çto mesN Ω = ∞. Klass¥ ob- lastej B1 ( g ), B2 ( g ) b¥ly vveden¥ v [12], hde poluçen¥ toçn¥e ocenky skoros- ty stabylyzacyy reßenyq zadaçy Nejmana dlq lynejn¥x parabolyçeskyx urav- nenyj vtoroho porqdka. Typyçn¥m prymerom oblastej klassa B2 ( g ) qvlqetsq oblast\ typa paraboloyda Ω h = x R x xN h∈ ′ <{ }: 1 , hde ′x = x xN2 2 2 1 2 +…+( ) / , x1 > 1, 0 ≤ h ≤ 1. V πtom sluçae (sm. [9] dlq N ≥ 2 y [12] pry N = 2 ) g ( v ) = c N Nmin ,( )v v− /( )1 γ , γ = h N h N ( ) ( ) − − + 1 1 1. (2.4) ISSN 1027-3190. Ukr. mat. Ωurn., 2006, t. 58, # 2 274 A. F. TEDEEV Dalee, çtob¥ yzbeΩat\ hromozdkyx formulyrovok rezul\tatov, budem pred- polahat\, çto a ( x ) ≡ a ( rk ( x ) ). Bolee toho, predpoloΩym, çto a ( ρ ) — rastu- waq funkcyq dlq vsex ρ > 0. Esly a1 ( s ) — ub¥vagwaq perestanovka funkcyy 1 / a ( rk ( x ) ), to sohlasno opredelenyg a1 ( s ) = 1 a r xk ( ) * ( )     = 1 a R s( )( ) . (2.5) Napomnym, çto pod ub¥vagwej perestanovkoj yzmerymoj funkcyy f ( x ) pony- maetsq sledugwee: f ( s ) * = inf ( )τ µ τ <{ }s , µ ( τ ) = mesn x f x∈ >{ }Ω: ( ) τ (sm., naprymer, [13]). PredpoloΩym, çto s a s q ( ) vozrastaet dlq vsex s > 0. (2.6) Vvedem teper\ ponqtye reßenyq zadaçy (1.1) – (1.3) v Q∞ = Ω × ( 0, ∞ ). Budem hovoryt\, çto u ( x, t ) — reßenye zadaçy (1.1) – (1.3) v Q∞ , esly u ≥ 0, u ∈ L QT∞, ( )loc ∩ C T L0 2, ; ( ),( )( )loc Ω , | D u σ | λ + 1 , a ( x ) | D u ν | q ∈ L QT1, ( )loc , σ = = ( m + λ – 1 ) / λ, dlq lgboho T > 0 y dlq lgboj funkcyy η ∈ C QT0 1( ) Q t m q T u u Du Du D a Du∫∫ − + +{ }− −η η ηλ ν1 1 d x d t = 0 . (2.7) Krome toho, u ( x, t ) → u0 pry t → 0 v L1 ( Ω ). Vopros o suwestvovanyy reßenyq zadaçy (1.1) – (1.3) predstavlqet samostoq- tel\n¥j ynteres y budet rassmotren v otdel\noj rabote. PreΩde çem perejty k toçn¥m formulyrovkam osnovn¥x rezul\tatov, vve- dem nekotor¥e oboznaçenyq. Pust\ P y ϕ — obratn¥e sootvetstvenno k V s sm( ) + − +λ λ2 1 y s a sH m q m+ − − + −( )[ ] /λ ν λ2 1 1 ( ) ( ) funkcyy. Zdes\ H = ( λ + + 1 ) ( ν q – 1 ) – q ( m + λ – 2 ). Osnovn¥my rezul\tatamy rabot¥ qvlqgtsq sledu- gwye teorem¥. Teorema 2.1. Pust\ u ( x, t ) — reßenye zadaçy (1.1) – (1.3) v Q∞ , suppu0 ⊂ ⊂ Ω( )ρ0 , ρ0 < ∞, Ω ∈ B2 ( g ) y v¥polnen¥ uslovyq (1.4) s m + λ – 2 > 0 y (2.6). Tohda spravedlyv¥ ocenky E ( t ) ≡ Ω ∫ ⋅u t dx( , ) ≤ cV t t a t t q q ϕ ϕ ϕ ν ( ) ( ) ( ) ( ) ( ) ( )     / −1 1 , (2.8) E ( t ) ≤ c a P V P P d t q q q 1 1 1 1 ∫ ( ) ( )        − − −/ ( ) ( ) ( ) ( ) τ τ τ τν ν , (2.9) u t( , ) ,⋅ ∞ Ω ≤ c t t m ϕ λ λ ( ) ( )+ + −    /1 1 2 (2.10) dlq vsex t > t0 = t u m 0 0 0 1 2ρ λ, ,Ω + −( ) . Teorema 2.2. Pust\ u ( x, t ) — reßenye zadaçy (1.1) – (1.3) v Ω h × ( 0, ∞ ), a ( x ) ≡ x1 α , 0 ≤ α < q, suppu0 ⊂ Ωh( )ρ0 , y v¥polnen¥ uslovyq (1.4) s m + λ – – 2 > 0, q > q * = N m N h h ( )+ − + + + + λ λ α ν 1 1 1 , (2.11) hde Nh = ( N – 1 ) h + 1. Tohda dlq dostatoçno bol\ßyx t > t1 = t u1 0 0 1ρ , ,Ω( ) ISSN 1027-3190. Ukr. mat. Ωurn., 2006, t. 58, # 2 NAÇAL|NO-KRAEVÁE ZADAÇY DLQ KVAZYLYNEJNÁX VÁROÛDAGWYXSQ … 275 E ( t ) ≥ c > 0. (2.12) Teorema 2.3. Pust\ u ( x, t ) — reßenye zadaçy (1.1) – (1.3) v Q∞ , Ω ∈ B2 ( g ) y v¥polnen¥ uslovyq (1.4) y (2.6) s ν = σ = ( m + λ – 1 ) / λ. Tohda spravedlyva ocenka E ( t ) ≤ c u dx V t t a tt q q q Ω Ω\ ( ) ( ) ( ) ( ) ( ) ( )ρ λ λ λ ρ ρ ρ( ) − −∫ + ( ) ( )        / /0 , (2.13) hde ρ ( t ) dlq vsex t > 0 opredelqetsq sledugwym obrazom: ρ ρλ λ λ λ λq m q ma( ) ( )( ) ( )+ − + + −( ) + −/2 1 2 = t q m( )( )− + − /λ λ λ1 . (2.14) Pryvedem prymer¥. Pust\ Ω = Ω h , α ≡ x1 α dlq x ≥ 1 y a ≡ 1 dlq 0 < x < < 1, 0 ≤ α < q. Tohda yz (2.8) poluçaem E ( t ) ≤ c t – Λ , (2.15) hde Λ = ( )( )*q q N H h− +ν 1 1 , H1 = H + α ( m + λ – 2 ); q * opredeleno v (2.11). Yz (2.15) vydno, çto esly q < q * , to E ( t ) → 0, t → ∞ . V tex Ωe predpoloΩenyqx pry q = q * yz (2.9) sleduet ocenka E ( t ) ≤ c t qln ( )[ ] − −/1 1ν . (2.16) Dalee, ocenka (2.10) prynymaet vyd u t( , ) ,⋅ ∞ Ω ≤ Ct q H− + + − /( )λ α1 1 . (2.17) Yz pryvedenn¥x rezul\tatov sleduet, çto q = q * yhraet rol\ krytyçeskoho pokazatelq v zadaçe (1.1) – (1.3). Kak vydno, πtot pokazatel\ zavysyt ne tol\ko ot m, λ, ν, no y ot heometryy oblasty y funkcyy a ( x ). Zametym pry πtom, çto esly h = 1, a ( x ) ≡ 1, to nov¥j krytyçeskyj pokazatel\ sovpadaet s poluçen- n¥m v [7] dlq sluçaq zadaçy Koßy. Ponqtno, çto sluçaj zadaçy Koßy ne ys- klgçaetsq yz dannoho yssledovanyq. Otmetym takΩe sledugwyj fakt: ocenky (2.17) y (2.10) ne zavysqt ot heometryy oblasty. Toçnost\ pryvedenn¥x rezul\- tatov podtverΩdaetsq tem, ç t o f u n k c y q u ( x, t ) = = ( ) ( )( ) ( )t t f x t tq H q m H+ +( )− + + − − − + −( )/ / 0 1 0 11 1λ α ν λ qvlqetsq reßenyem uravne- nyq (1.1) s a = x α . Pry πtom f ( r ) udovletvorqet uravnenyg − + + − + − + −    λ α ν λ1 1 1 1 q H f r q m H r fr( ) ( ) = r d dr r f f fN N m r r − − − − −( )( )1 1 1 1λ – – r f r qα ν( ) . Dalee, teorema 2.3 spravedlyva y v nev¥roΩdennom sluçae. Naprymer, esly m + λ – 2 = 0, to ρ ( t ) = t1 1/ +( )λ , y esly suppu0 < ∞, to yz (2.3) sleduet E ( t ) ≤ cV t t a tq q q1 1 1 1 1/ / / /+ − − +[ ] + − −( ) ( )[ ]( ) ( )( ) ( ) ( )λ λ λ λ λ λ . (2.18) Zametym, çto yz uslovyj (1.4) pry ν = ( m + λ – 1 ) / λ poluçaem λ < q < λ + 1. Krytyçnost\ Ωe pokazatelq q v (2.18) opredelqetsq uslovyem stremlenyq k nulg pry t → ∞ pravoj çasty v (2.18). Po-vydymomu, ocenka (2.18) qvlqetsq novoj daΩe v sluçae λ = 1. V zaklgçenye πtoho punkta pryvedem vspomohatel\noe utverΩdenye, qvlqg- weesq çastn¥m sluçaem lemm¥ 3.1 [14]. ISSN 1027-3190. Ukr. mat. Ωurn., 2006, t. 58, # 2 276 A. F. TEDEEV Lemma 2.1. Pust\ Ω ∈ B1 ( g ) y v¥polneno uslovye: s a s p ( ) vozrastaet dlq s > 0, p > 1. Tohda ymeet mesto neravenstvo Ω ∫ ( )a r x Du dxk p( ) ≥ c E G E E p p p p p β β β β/ − / −( )( ) ( ) (2.19) dlq 0 < β < p, G ( s ) = s g s a R s p ( ) ( )     ( ) 1 , Eγ = Ω ∫ u dxγ . Esly sup ( )pu x ⊂ Ω( )ρ , to oçevydn¥m sledstvyem (2.19) qvlqetsq neraven- stvo Puankare Ω( )ρ ∫ u d xp ≤ c a a Du d x p pρ ρ ρ ( ) ( )Ω ∫ . (2.20) 3. Dokazatel\stvo osnovn¥x rezul\tatov. Dokazatel\stvo teore- m¥�2.1. DokaΩem snaçala, çto Z ( t ) = inf { r > 0 : u ( x, t ) = 0, p. v. x ∈ Ω \ Ω ( r ) } ≤ c φ ( t ). (3.1) Rassmotrym posledovatel\nost\ rn = 2 ρ ( 1 – 2 – n – 1 ), n = 0, 1, … , ρ > 2ρ0 . Pust\ ζn kr x( )( ) — posledovatel\nost\ hladkyx funkcyj, udovletvorqgwyx uslovyqm: ζn = 0 pry x ∈ Ω ( rn ), ζn ≡ 1 pry x ∈ Ω \ Ω rn( ) , hde rn = r rn n+ +1 2 , y | D ζn | ≤ c 2 n ρ – 1 . Tohda, umnoΩaq obe çasty uravnenyq (1.1) na ζλ θ n u+1 , θ > 0, y yntehryruq po Qt , poluçaem yn + 1 ≡ sup 0 1 < < +∫ τ θ t Un u d x + 0 2 1 t U m n u Du d x d∫ ∫ + − +θ λ τ + + 0 t U q n u Du d x d∫ ∫ θ ν τ ≤ c u d x d n t U U m n n 2 1 1 0 1 ( ) \ λ λ λ θ ρ τ + + + + −∫ ∫ , (3.2) hde Un = Ω \ Ω ( rn ), Un = Ω \ Ω rn( ) . Toçno tak Ωe, kak v rabote [9], dokaz¥vaet- sq neravenstvo yn + 1 ≤ c t y f t y n K n m K m2 1 1 1 1 1 2 1 0 0 2 11 1 ( ) ( )( ) ( )( ) ( ) ( ) λ λ θ λ λ λ λ θ ρ θ θ + + + + + + − + + − +/ / /+ + ( ), (3.3) hde f s0( ) = F s sN K m 1 1 1 2 11 1( ) ( ) ( ) ( ) − + + − +        / / +θ λ θ θ , K1 + θ = N ( m + λ – 2 ) + ( 1 + θ )( λ + 1 ), F1 1( )− — obratnaq k F1 ( s ) = s g sλ λ β λ+ + − +/( ) ( )1 1 1 funkcyq. Perepyßem (3.3) v vyde y A n a +1 ≤ c n2 1( )λ+ , (3.4) hde ISSN 1027-3190. Ukr. mat. Ωurn., 2006, t. 58, # 2 NAÇAL|NO-KRAEVÁE ZADAÇY DLQ KVAZYLYNEJNÁX VÁROÛDAGWYXSQ … 277 a = 1 2 1 1 1 + + − +   + − ( )( )m K λ λ θ , A = t f t yK m a( )( ) ( ) ( )1 1 1 0 0 2 11+ + − − + − + −/ /+ ( )[ ]θ λ λ λ θθ ρ . Nam potrebuetsq ewe odno rekurrentnoe neravenstvo. Poskol\ku yzvestno [9], çto Z ( t ) ≤ c P t u m 0 1 2 0,Ω + −( ) +[ ]λ ρ , (3.5) to, yspol\zuq neravenstvo Puankare (2.20) s p = q, poluçaem 0 t U q n w d x d∫ ∫ τ ≤ c a a Dw d x dq t U q n ρ ρ τ( )( )− ∫ ∫1 0 ≤ ≤ c Z t a Z t y q n ( ) ( )( ) , w = u q q( )ν θ+ / . (3.6) Takym obrazom, prymenqq k pravoj çasty (3.2) neravenstvo Hel\dera, v sylu (3.6) naxodym yn + 1 ≤ c u d x d n t U m n 2 1 1 0 1 ( )λ λ λ θ ρ τ + + + + −∫ ∫ ≤ ≤ c tV Z t a Z t y n q m q q m q n m q2 1 1 1 1 1 ( ) ( ) ( ) ( ) ( ) ( ) ( )( ) ( ) ( ) λ λ ν λ ν θ λ θ ν θ λ θ ν θ ρ ρ + + − + −( ) + + + − + + + − +[ ] ( )       / / / . (3.7) Perepyßem neravenstvo (3.7) v vyde y B n b +1 ≤ c n2 1( )λ+ yn , (3.8) hde b = ν θ λ θ q m + + + − 1 > 1, poskol\ku ν q > m + λ – 1, B = tV Z t a Z t q m q q b ( ) ( ) ( ) ( ) ( )ρ ρν λ ν θ λ[ ] ( )       − + −( ) + − −/1 1 . Obæedynqq teper\ neravenstva (3.4) y (3.8), s uçetom neravenstva Gnha poluçaem y A B n+ − 1 1 1 1 1 ε ε ε ≤ c y A y B n a n b + ++     1 1 ≤ c n2 1( )λ+ yn , hde ε1 = b b a+ −1 < 1. Sledovatel\no, v sylu yteratyvnoj lemm¥ 5.6 [15, c. 113] zaklgçaem, çto yn → 0, n → ∞, A y B a b( )( ) 0 1− / ≤ c0 . (3.9) Dlq ocenky y0 rassmotrym posledovatel\nost\ y ( n ) = sup ( , ) ( )0 1 < < > +∫ ⋅ τ ρ θτ t r xk n u d x + 0 2 1 t r x m k n u Du d x d∫ ∫ > + − + ( ) ρ θ λ τ + + 0 t r x q k n u Du d x d∫ ∫ >( ) ρ θ ν τ , ρn = ρ( )1 2 2 + n . ISSN 1027-3190. Ukr. mat. Ωurn., 2006, t. 58, # 2 278 A. F. TEDEEV RassuΩdaq toçno tak Ωe, kak pry dokazatel\stve (3.8), ymeem y n b( )( ) ≤ ≤ c n2 1( )λ+ y ( n + 1 )B. Yteryruq poslednee neravenstvo, poluçaem ocenku y0 = y ( 0 ) ≤ ≤ ctV Z t a Z t q m q m q q m( ) ( ) ( ) ( ) ( ) ( )( ) ( )ρ ρ λ θ ν λ λ ν θ ν λ ( )       + + − − + −( ) − + + − + −( ) / / 1 1 1 1 . (3.10) Podstavlqq (3.10) v (3.9) y uçyt¥vaq oçevydnoe neravenstvo Z ( t ) ≤ 2 ρ, pryxo- dym k v¥vodu, çto u ≡ 0, esly ρ H a ( ρ ) m + λ – 2 ≥ c t q m 1 1ν λ− + −( ) . ∏to y dokaz¥vaet ocenku (3.1). Dalee, umnoΩym obe çasty (1.1) na u θ y proyntehryruem rezul\tat po Ω ( ρ ) s ρ = Z ( t ). V rezul\tate poluçym 1 1 1 θ τ ρ θ + ∫ +d d u d x Ω( ) = – θ ρ θ λ Ω( ) ∫ + − +u Du d xm 2 1 – – c a Du d xq q q Ω( ) ( ) ρ ν θ∫ + / ≤ – c a Du d xq q q Ω( ) ( ) ρ ν θ∫ + / . (3.11) Prymenqq teper\ neravenstva Hel\dera y Puankare, poluçaem Ω( )ρ θ∫ +u d x1 ≤ V u d xq q q q ( )( ) ( ) ( ) ( ) ( ) ρ ν ν θ ρ ν θ θ ν θ − + + + + / / ∫       1 1 Ω ≤ ≤ cV a a Du d xq q q q q q q q ( ) ( )( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ρ ρ ρν ν θ θ ν θ ρ ν θ θ ν θ − + − + + + + + / / / / [ ]      ∫1 1 1 1 Ω . Sledovatel\no, yz (3.11) ymeem d d u d x τ ρ θ Ω( ) ∫ +1 ≤ −     − − + − + + + / / ∫cV a u d xq q q ( ) ( )( ) ( ) ( ) ( ) ( ) ρ ρ ρν θ ρ θ ν θ θ 1 1 1 1 Ω . Yntehryruq πto neravenstvo, lehko naxodym Ω( )ρ θ∫ +u d x1 ≤ cV a tq q ( ) ( ) ( ) ( ) ρ ρ ρ θ ν− − + −[ ] /1 1 1 1 . Nakonec, prymenqq neravenstvo Hel\dera, s uçetom pred¥duweho neravenstva poluçaem Ω Z t u t d x ( ) ( , ) ( ) ∫ ⋅ ≤ Ω Z t u d x V Z t ( ) ( ) ( )( ) ( ) + + +∫       ( ) / /1 1 1 1θ θ θ θ ≤ ≤ V Z t Z t a Z t t V Z tq q ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( )( ) ( )( )[ ] ( )− − + − + +/ / /1 1 1 1 1 1 1θ ν θ θ θ ≤ ≤ cV t t a t tq q ϕ ϕ ϕ ν ( ) ( ) ( ) ( )( ) ( )[ ]− − −/1 1 1 1 . DokaΩem ocenku (2.9). Yntehryruq uravnenye (1.1) po Ω ( ρ ), ρ = Z ( t ), poluçaem dE t dt ( ) = – D ( t ), (3.12) hde ISSN 1027-3190. Ukr. mat. Ωurn., 2006, t. 58, # 2 NAÇAL|NO-KRAEVÁE ZADAÇY DLQ KVAZYLYNEJNÁX VÁROÛDAGWYXSQ … 279 E ( t ) = Ω( ) ( , ) ρ ∫ ⋅u t d x , D ( t ) = Ω( )ρ ν∫ a Du d x q . Prymenqq neravenstva Hel\dera y Puankare, ymeem E ( t ) ≤ Ω( ) ( ) ( ) ( )( ) ρ ν ν ν νρ∫     / /−u d x Vq q q q 1 1 ≤ c a D t V q q q qρ ρ ρ ν ν ν ( ) ( ) ( ) ( ) ( ) ( )      / /− 1 1 . (3.13) Poskol\ku yz (3.5) pry dostatoçno bol\ßyx t > t0 sleduet, çto Z ( t ) ≤ c P ( t ), yz neravenstv (3.12) y (3.13) v¥tekaet dE t dt ( ) ≤ – c a P t V P t P t E tq q q( ) ( ) ( ) ( ) ( ) ( )    −ν ν 1 . (3.14) Sledovatel\no, yntehryruq (3.14) ot t0 do t, poluçaem E ( t ) ≤ c a P V P P d t t q q q 0 1 1 1 ∫ ( ) ( )        − − −/ ( ) ( ) ( ) ( ) τ τ τ τν ν . Teorema 2.1 dokazana. Dokazatel\stvo teorem¥ 2.2. Dlq lgb¥x 0 < t1 < t ymeem E ( t1 ) = E ( t ) + t t q x Du d x d 1 1∫ ∫ Ω α ν τ . (3.15) Prymenqq neravenstvo Hel\dera, poluçaem t t q x Du d x d 1 1∫ ∫ Ω α ν τ ≤ t t m q u Du d x d 1 2 1 1 ∫ ∫ + − + +        / Ω θ λ λ τ ( ) × × t t q q m q q x u d x d 1 1 1 1 1 1 1 1 1 ∫ ∫ + + − + − + − −( ) + − + − + / / /       Ω α λ λ λ ν λ θ λ λ λ τ( ) ( ) ( ) ( ) ( ) ( ) ( ) ≡ ≡ J Jq q 1 1 2 1 1/ /+ + − +( ) ( ) ( )λ λ λ , (3.16) hde θ > 0 — dostatoçno maloe çyslo. UmnoΩaq obe çasty (1.1) na u θ y ynteh- ryruq po Ω × ( t1 , t ), ymeem J1 ≤ c Ω ∫ + ⋅u t d x1 1 θ( , ) . (3.17) Dalee nam potrebuetsq sledugwaq ocenka dlq Ω ∈ B1 ( g ) [8, 9]: u t( , ) ,⋅ ∞ Ω ≤ c t E d t t E d t t t t m − − + − / / ∫ ∫        1 2 1 2 2 ( ) ( ) τ τ ψ τ τ λ , (3.18) hde ψ — obratnaq k Ψ ( z ) = z z g zm+ − +/( )λ λ2 1( ) funkcyq. V çastnosty, esly Ω = Ω h , to v sylu (2.4) dlq z > 1 ψ ( z ) = = cz m N Nh h( )+ − + +( ) /λ λ2 1 . Sledovatel\no, s uçetom toho, çto E ( t ) ≤ u0 1,Ω ∀ t > > 0, yz (3.18) dlq t > 1 poluçaem u t( , ) ,⋅ ∞ Ω ≤ c u tK N Kh h h 0 1 1 ,Ω λ+( ) −/ / , (3.19) ISSN 1027-3190. Ukr. mat. Ωurn., 2006, t. 58, # 2 280 A. F. TEDEEV hde Kh = ( m + λ – 2 ) Nh + λ + 1. Tohda Ω ∫ + ⋅u t d x1 θ( , ) ≤ E t u t( ) ( , ) ,1 1⋅ ∞ Ω θ ≤ cE t u tK N Kh h h( ) ,1 0 1 1 Ω λ θ θ+( ) −/ / . (3.20) Otmetym ewe, çto dlq Ω = Ω h Z t( ) ≤ c u tm K Kh hρ λ 0 0 1 2 1+( )+ − / / , ( ) Ω ≤ ≤ 2 0 1 2 1c u tm K Kh h , ( ) Ω + − / /λ ≡ ˜ ( )Z t dlq t > t0 = ρ λ 0 0 1 2K mh u ,Ω + − . Sledovatel\no, dlq t0 < t1 < t ymeem J2 ≤ c E Z u d t t q H q q 1 1 1 1∫ + + − ∞ − + −/ /⋅( ) ˜( ) ( , )( ) ( ) , ( ) ( )τ τ τ τα λ λ θ λ Ω ≤ ≤ c u E t dm H q K q t t HN qN q Kh h h h 0 1 2 1 1 1 1 1 1 , ( ) ( )( ) ( ) ( ) ( )( )Ω + − + − +( ) + −( ) − − − +( ) + −[ ]/ /∫λ α θ λ λ θ α λ λτ τ . (3.21) Poskol\ku q > q * , yntehral v pravoj çasty (3.21) sxodytsq pry θ < < ( )( )*q q N qN h h − +ν 1 . Obæedynqq ocenky (3.15) – (3.17), (3.21), naxodym E ( t1 ) ≤ E ( t ) + c u t E tH K q q N Kh h h* , ( )* ( )0 1 1 1Ω / /− − (3.22) dlq vsex t1 > t0 . V¥berem teper\ t1 : t1 = max , * , ( )( )* t c u H K K q q N h h h 0 0 1 1 2 1 Ω / /( )      − +[ ]ν . Tohda yz (3.22) lehko v¥vodym ocenku 2 E ( t ) ≥ E ( t1 ) dlq vsex t > t1 . Otmetym takΩe [7] (lemma 4.1), çto sluçaj u ( x, t1 ) ≡ 0 dlq vsex x ∈ R N y nekotoroho t1 > 0 ne ymeet mesta. Teorema 2.2 dokazana. Dokazatel\stvo teorem¥ 2.3. Ymeem E ( t ) = Ω ∫ ⋅u t d x( , ) = Ω( ) ( , ) ρ ∫ ⋅u t d x + Ω Ω\ ( ) ( , ) ρ ∫ ⋅u t d x ≡ I1 + I2 . (3.23) Sohlasno neravenstvu Hel\dera I1 ≤ Ω( ) ( ) ( ) ( )( ) ρ ν ν ν νρ∫     / /−u d x Vq q q q 1 1 . (3.24) Pust\ u ν = v. Tohda, prymenqq lemmu 2.1 s β = ν – 1 < q, p = q, poluçaem D ( t ) ≡ Ω ∫ a D d xqv ≥ c F t G E t F t q q q q q ( ) ( ) ( )( ) ( )ν ν ν/ /− − −( )1 1 1 , (3.25) hde Fq ( t ) = Ω ∫ ⋅v( , )t d xq , G ( s ) = s g s a R s q ( ) ( )     ( )( )−1 . Napomnym, çto s g s( ) ∼ R ( s ) dlq Ω ∈ B2 ( g ). Yz (3.25) sleduet, çto ISSN 1027-3190. Ukr. mat. Ωurn., 2006, t. 58, # 2 NAÇAL|NO-KRAEVÁE ZADAÇY DLQ KVAZYLYNEJNÁX VÁROÛDAGWYXSQ … 281 Fq ( t ) ≤ c E t G D t E t q q q ( ) ( ) ( ) ( )ν ν ν 1 1 1 − −          , (3.26) hde G1 ( s ) = s G s qν − − 1 1( ) , G1 1( )− — obratnaq k G1 funkcyq. Dalee, yntehryruq (1.1) po Ω, ymeem d dt E t( ) = – D ( t ). Takym obrazom, yz (3.23), (3.24), (3.26) polu- çaem neravenstvo E ( τ ) ≤ c E V G d d E Eq q q q q ( ) ( ) ( ) ( )( ) ( ) ( ) ( ) ( ) ( ) τ ρ τ τ τν ν ν ν ν − − − − / / −       { }1 1 1 1 + I2 ( τ ). (3.27) Dlq ocenky I2 ( τ ) postupym sledugwym obrazom. Pust\ ζ ( x ) = ζ ( rk ( x ) ) — hladkaq funkcyq, ravnaq 1 pry rk ( x ) > ρ, nulg pry rk ( x ) < ρ / 2, 0 ≤ ζ ≤ 1, 0 < < rk < ∞. Krome toho, | D ζ | ≤ c / ρ. UmnoΩym obe çasty (1.1) na ζ s , s ≥ λ + 1, y rezul\tat proyntehryruem po Ω. V rezul\tate poluçym d d u d xs τ ζ τ Ω ∫ ⋅( , ) + Ω ∫ a Du d x q sν ζ ≤ c Du d xs q ρ ζ ρ ρ ν Ω Ω( ) \ \ 2 1 ( ) −∫ , ν = m + −λ λ 1 . Prymenqq k pravoj çasty neravenstvo Gnha, poluçaem d d u x d xs τ ζ τ Ω ∫ ( , ) + Ω ∫ a Du d x q sν ζ ≤ ≤ c q a Du d xq qλ ε λ ν/ ∫ Ω + c q q a r x d x q q q k q− ( ) − − − ( ) − − / / /∫λ ε ρ λ λ λ ρ ρ λ λ ( ) ( ) ( ) ( ) \ \ ( ) Ω Ω 2 . Polahaq c q qλ ε λ/ = 1 / 2, yz posledneho neravenstva ymeem d d u d xs τ ζ τ Ω ∫ ⋅( , ) ≤ c V aq q q ( ) ( )( ) ( ) ρ ρ ρλ λ λ/ /− − . Nakonec, yntehryruq πto neravenstvo, naxodym Ω ∫ ζ τsu x d x( , ) ≤ Ω ∫ ζsu d x0 + c V aq q q τ ρ ρ ρλ λ λ ( ) ( )( ) ( )/ /− − ≡ ≡ ˜ ( , )F ρ τ ≤ ˜ ( , )F tρ , t1 < τ < t. (3.28) Dalee, otmetym, çto G1 ( s ) = s s g sN N qε0 1 1( ) ( )− −/[ ] , ε0 = N q q N ( )ν − +1 . Znaçyt, G s s 1 0 ( ) ε vozrastaet. ∏to oznaçaet, çto funkcyq s G s q q q 1 1 1( ) ( ) ( ) ( )− − −( ) /ν ν ν = = s G s sqN q q q q/ / /− − − −( )[ ]ε ν ν ν ν ε0 0 1 1 1 1( ) ( ) ( ) ( )( ) takΩe vozrastaet. Takym obrazom, yz (3.27) y (3.28) sleduet dy dτ ≤ −         / − −c E t G y E t Vq q q ( ) ( ) ( ) ( ) ( ) 1 1 1 1 1ν ν ντ ρ ≤ ≤ − ( )− − − −/ /c E t y G Vq q q q q( ) ( ) ( )( ) ( ) 1 1 1 1 10 0ν ν ε ν ν ε ντ ρ , (3.29) ISSN 1027-3190. Ukr. mat. Ωurn., 2006, t. 58, # 2 282 A. F. TEDEEV hde y ( τ ) = E ( τ ) – ˜ ( , )F tρ . Ytak, pry t1 = σ t, σ ∈ (0, 1), yntehryruq (3.29) ot σ t do t, poluçaem E ( t ) ≤ ≤ c E t tq q q q q q( ) ( ) ( ) ( ) ( )σ σδ ν ν ε ν ν ν ε ν− − − + − − − +/ /1 1 1 10 0 × × G V q q q 1 1 1 10( ) ( ) ( ) ρ ν ν ε ν− − − +( ) / + ˜ ( , )F tρ , (3.30) hde δ = ν ν ν q q N q 2 2 21+ −( ) < 1. Nakonec, yteryruq (3.30) po σ, ymeem E ( t ) ≤ ct G Vq q− − − − −/ /( )1 1 1 1 1 1( ) ( ) ( )ν ν ρ + c ˜ ( , )F tρ . Zameçaq teper\, çto G V1 1( )ρ −( ) ∼ V aq q q( ) ( )( ) ( )ρ ρ ρν ν/ /− − −1 1 1 y naxodq ρ yz uslovyq ρ ρλ λ λ λ λ( ) ( )( ) ( )( )t a tq m q m+ − + + −( ) + −/ ( )2 1 2 = t q m( )( )− + − /λ λ λ1 , pryxodym k trebuemomu utverΩdenyg. Teorema 2.3 dokazana. 1. Chipot M., Weissler F. B. Some blow-up results for a nonlinear parabolic equation with a gradient term // SIAM J. Math. Anal. – 1989. – 20. – P. 886 – 907. 2. Souplet Ph. Resent results and open problems on parabolic equations with gradient nonlinearities // J. Different. Equat. – 2001. – # 20. – P. 1 – 19. 3. Laurencot Ph., Souplet Ph. On the growth of mass for a viscous Hamilton – Jacobi equation. – 2002. – Preprint. 4. Ben-Arti M., Souplet Ph., Wessler F. B. The local theory for viscous Hamilton – Jacobi equations in Lebesgus spaces // J. Math. Pures and Appl. – 2002. – 81. – P. 343 – 378. 5. Souplet Ph. Gradient blow-up for multidimensional nonlinear parabolic equations with general boundary conditions. – 2002. – Preprint. 6. Benachour S., Laurencot Ph., Schmidt D., Souplet Ph. Extinction and non-extincion for viscous Hamilton – Jacobi equations in R N. – 2002. – Preprint. 7. Andreucci D., Tedeev A. F., Ughi M. The Cauchy problem for degenerate parabolic eqautions with source and damping // Ukr. Math. Bull. – 2004. – 1, # 1. – P. 1 – 23. 8. Tedeev A. F. Ocenky skorosty stabylyzacyy pry t → ∞ reßenyq vtoroj smeßannoj zadaçy dlq kvazylynejnoho parabolyçeskoho uravnenyq vtoroho porqdka // Dyfferenc. uravnenyq. – 1991. – 27, # 10. – S. 1795 – 1806. 9. Andreucci D., Tedeev A. F. A Fujita type result for degenerate Neumann problem in domains with noncompact boundary // J. Math. Anal. and Appl. – 1999. – 231. – P. 543 – 567. 10. Andreucci D., Tedeev A. F. Optimal bounds and blow-up phenomena for parabolic problems in narrowing domains // Proc. Poy. Soc. Edinburgh A. – 1998. – 128, # 6. – P. 1163 – 1180. 11. Andreucci D., Tedeev A. F. Sharp estimates and finite speed of propagation for a Neumann problem in domains narrowing at infinity // Adv. Different. Equat. – 2000. – 5. – P. 833 – 860. 12. Huwyn A. K. Ob ocenkax reßenyj kraev¥x zadaç dlq parabolyçeskoho uravnenyq vtoroho porqdka // Tr. Mat. yn-ta AN SSSR. – 1973. – 126. – S. 5 – 45. 13. Talenti G. Elliptic equations and rearrangements // Ann/ Scuola norm. super. Pisa. – 1976. – 4, #73. – P. 697 – 718. 14. Andreucci D., Cirmi G. R., Leonardi S., Tedeev A. F. Large time behavior of solutions to the Neumann problem for a quasilinear second order degenerate parabolic equations in domains with noncompact boundary // J. Different. Equat. – 2001. – 174. – P. 253 – 288. 15. Lad¥Ωenskaq O. A., Solonnykov V. A., Ural\ceva N. N. Lynejn¥e y kvazylynejn¥e uravne- nyq parabolyçeskoho typa. – M.: Nauka, 1967. – 736 s. Poluçeno 10.10.2005 ISSN 1027-3190. Ukr. mat. Ωurn., 2006, t. 58, # 2
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spelling umjimathkievua-article-34512020-03-18T19:54:47Z Initial-boundary-value problems for quasilinear degenerate hyperbolic equations with damping. Neumann problem Начально-краевые задачи для квазилинейных вырождающихся параболических уравнений с демпфированием. Задача Неймана Tedeev, A. F. Тедеев, А. Ф. Тедеев, А. Ф. We study the behavior of the total mass of the solution of Neumann problem for a broad class of degenerate parabolic equations with damping in spaces with noncompact boundary. New critical indices for the investigated problem are determined. Досліджується поведінка тотальної маси розв&#039;язку задачі Неймана для широкого класу вироджених параболічних рівнянь з демпфіруванням у просторах із некомпактною межею. Знайдено нові критичні показники в досліджуваній задачі. Institute of Mathematics, NAS of Ukraine 2006-02-25 Article Article application/pdf https://umj.imath.kiev.ua/index.php/umj/article/view/3451 Ukrains’kyi Matematychnyi Zhurnal; Vol. 58 No. 2 (2006); 272–282 Український математичний журнал; Том 58 № 2 (2006); 272–282 1027-3190 rus en https://umj.imath.kiev.ua/index.php/umj/article/view/3451/3640 https://umj.imath.kiev.ua/index.php/umj/article/view/3451/3641 Copyright (c) 2006 Tedeev A. F.
spellingShingle Tedeev, A. F.
Тедеев, А. Ф.
Тедеев, А. Ф.
Initial-boundary-value problems for quasilinear degenerate hyperbolic equations with damping. Neumann problem
title Initial-boundary-value problems for quasilinear degenerate hyperbolic equations with damping. Neumann problem
title_alt Начально-краевые задачи для квазилинейных вырождающихся параболических уравнений с демпфированием. Задача Неймана
title_full Initial-boundary-value problems for quasilinear degenerate hyperbolic equations with damping. Neumann problem
title_fullStr Initial-boundary-value problems for quasilinear degenerate hyperbolic equations with damping. Neumann problem
title_full_unstemmed Initial-boundary-value problems for quasilinear degenerate hyperbolic equations with damping. Neumann problem
title_short Initial-boundary-value problems for quasilinear degenerate hyperbolic equations with damping. Neumann problem
title_sort initial-boundary-value problems for quasilinear degenerate hyperbolic equations with damping. neumann problem
url https://umj.imath.kiev.ua/index.php/umj/article/view/3451
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