In this paper,we shall exploit the Freud method in the Classical operator approximation theory to im- prove known quantitative estimalions with an emphasis on Calculah' on the generic constants.
Let L = --△ ＋ Ⅴ be the SchrSdinger operator on Rd, d ≥ 3, where A is the Laplacian on Rd and V ≠ 0 is a nonnegative function satisfying the reverse HSlder inequality. In this article, the author investigates some...Let L = --△ ＋ Ⅴ be the SchrSdinger operator on Rd, d ≥ 3, where A is the Laplacian on Rd and V ≠ 0 is a nonnegative function satisfying the reverse HSlder inequality. In this article, the author investigates some properties of the Riesz potential IaL associated with L on the Campanato-type spaces ∧Lβ and the Hardy-type spaces HLP.展开更多
In this article, we consider compound matrices and compound operator equations in a Hilbert space. First, we recall some concepts and main results introduced by Muldowney and by Roger Temam. After that we establish th...In this article, we consider compound matrices and compound operator equations in a Hilbert space. First, we recall some concepts and main results introduced by Muldowney and by Roger Temam. After that we establish the rule of compound matrices in a Hilbert space, and obtain the expression of solution to a compound operator equation by using the method of operator semigroup. Our brief results generalize the corresponding results in a finite space.展开更多
Recently in [4], the Jessen＇s type inequality for normalized positive C0-semigroups is obtained. In this note, we present few results of this inequality, yielding Holder＇s Type and Minkowski＇s type inequalities for...Recently in [4], the Jessen＇s type inequality for normalized positive C0-semigroups is obtained. In this note, we present few results of this inequality, yielding Holder＇s Type and Minkowski＇s type inequalities for corresponding semigroup. Moreover, a Dresher＇s type inequality for two-parameter family of means, is also proved.展开更多
The neural operator theory ofers a promising framework for efficiently solving complex systems governed by partial diferential equations(PDEs for short).However,existing neural operators still face significant challen...The neural operator theory ofers a promising framework for efficiently solving complex systems governed by partial diferential equations(PDEs for short).However,existing neural operators still face significant challenges when applied to spatiotemporal systems that evolve over large time scales,particularly those described by evolution PDEs with time-derivative terms.This paper introduces a novel neural operator designed explicitly for solving evolution equations based on the theory of operator semigroups.The proposed approach is an iterative algorithm where each computational unit,termed the single-step neural operator solver(SSNOS for short),approximates the solution operator for the initial-boundary value problem of semilinear evolution equations over a single time step.The SSNOS consists of both linear and nonlinear components:The linear part approximates the linear operator in the solution map;in contrast,the nonlinear part captures deviations in the solution function caused by the equations nonlinearities.To evaluate the performance of the algorithm,the authors conducted numerical experiments by solving the initial-boundary value problem for a two-dimensional semilinear hyperbolic equation.The experimental results demonstrate that their neural operator can efficiently and accurately approximate the true solution operator.Moreover,the model can achieve a relatively high approximation accuracy with simple pre-training.展开更多
We prove that the group of weighted composition operators induced by continuous automorphism groups of the upper half plane U is strongly continuous on the weighted Dirichlet space of U,Dα(U).Further,we investigate w...We prove that the group of weighted composition operators induced by continuous automorphism groups of the upper half plane U is strongly continuous on the weighted Dirichlet space of U,Dα(U).Further,we investigate when they are isometries on Dα(U).In each case,we determine the semigroup properties while in the case that the induced composition group is an isometry,we apply similarity theory to determine the spectral properties of the group.展开更多
Existence and regularity of solutions to model for liquid mixture of 3He-4He is considered in this paper. First, it is proved that this system possesses a unique global weak solution in H^1 （Ω, C ×R） by using ...Existence and regularity of solutions to model for liquid mixture of 3He-4He is considered in this paper. First, it is proved that this system possesses a unique global weak solution in H^1 （Ω, C ×R） by using Galerkin method. Secondly, by using an iteration procedure, regularity estimates for the linear semigroups, it is proved that the model for liquid mixture of 3He-4He has a unique solution in H^k（Ω, C × R） for all k ≥ 1.展开更多
In this paper we prove that the initial-boundary value problem for the nonlinear evolution equation ut = △u ＋ λu - u^3 possesses a global attractor in Sobolev space H^k for all k≥0, which attracts any bounded doma...In this paper we prove that the initial-boundary value problem for the nonlinear evolution equation ut = △u ＋ λu - u^3 possesses a global attractor in Sobolev space H^k for all k≥0, which attracts any bounded domain of H^k（Ω） in the H^k-norm. This result is established by using an iteration technique and regularity estimates for linear semigroup of operator, which extends the classical result from the case k ∈ [0, 1] to the case k∈ [0, ∞）.展开更多
In this article, some properties of complex Wiener-It? multiple integrals and complex Ornstein-Uhlenbeck operators and semigroups are obtained. Those include Stroock’s formula, Hu-Meyer formula, Clark-Ocone formula, ...In this article, some properties of complex Wiener-It? multiple integrals and complex Ornstein-Uhlenbeck operators and semigroups are obtained. Those include Stroock’s formula, Hu-Meyer formula, Clark-Ocone formula, and the hypercontractivity of complex Ornstein-Uhlenbeck semigroups. As an application, several expansions of the fourth moments of complex Wiener-It? multiple integrals are given.展开更多
In this paper we discuss tLhe existence results of the integral solutions to nonlinear evolution inclusion: u' (t) ∈ Au(t) +F(t,u(t)), where A is m-dissipative and F is a set valued map in separable Banach spaces...In this paper we discuss tLhe existence results of the integral solutions to nonlinear evolution inclusion: u' (t) ∈ Au(t) +F(t,u(t)), where A is m-dissipative and F is a set valued map in separable Banach spaces, and extend the relative results in references.展开更多
The weighted Sobolev-Lions type spaces W pl,γ（Ω; E0, E） = W pl,γ（Ω; E） ∩ Lp,γ （Ω; E0） are studied, where E0, E are two Banach spaces and E0 is continuously and densely embedded on E. A new concept of capa...The weighted Sobolev-Lions type spaces W pl,γ（Ω; E0, E） = W pl,γ（Ω; E） ∩ Lp,γ （Ω; E0） are studied, where E0, E are two Banach spaces and E0 is continuously and densely embedded on E. A new concept of capacity of region Ω ∈ Rn in W pl,γ（; E0, E） is introduced. Several conditions in terms of capacity of region Ω and interpolations of E0 and E are found such that ensure the continuity and compactness of embedding operators. In particular, the most regular class of interpolation spaces Eα between E0 and E, depending of α and l, are found such that mixed differential operators Dα are bounded and compact from W pl,γ（Ω; E0, E） to Eα-valued Lp,γ spaces. In applications, the maximal regularity for differential-operator equations with parameters are studied.展开更多
In this paper, we discuss the existence and uniqueness of mild solutions of random impulsive abstract neutral partial differential equations in a real separable Hilbert space. The results are obtained by using Leray-S...In this paper, we discuss the existence and uniqueness of mild solutions of random impulsive abstract neutral partial differential equations in a real separable Hilbert space. The results are obtained by using Leray-Schauder Alternative and Banach Contraction Principle.Finally an example is given to illustrate our problem.展开更多
In this paper,the existence,uniqueness and Strichartz type estimates to solutions of multipoint problem for abstract linear and nonlinear wave equations are obtained.The equation includes a linear operator A defined i...In this paper,the existence,uniqueness and Strichartz type estimates to solutions of multipoint problem for abstract linear and nonlinear wave equations are obtained.The equation includes a linear operator A defined in a Hilbert space H.We obtain the existence,uniqueness regularity properties,and Strichartz type estimates to solutions of a wide class of wave equations which appear in the fields of elastic rod,hydro-dynamical process,plasma,materials science and physics,by choosing the space H and the operator A.展开更多
Bracketed words are basic structures both in mathematics （such as Rota-Baxter algebras） and mathematical physics （such as rooted trees） where the locations of the substructures are important. In this paper, we giv...Bracketed words are basic structures both in mathematics （such as Rota-Baxter algebras） and mathematical physics （such as rooted trees） where the locations of the substructures are important. In this paper, we give the classification of the relative locations of two bracketed subwords of a bracketed word in an operated semigroup into the separated, nested, and intersecting cases. We achieve this by establishing a correspondence between relative locations of bracketed words and those of words by applying the concept of Motzkin words which are the algebraic forms of Motzkin paths.展开更多
Properties for tensor products of semigroups are considered and the solutions of the equationAC - CB = Q are discussed. Results obtained in this paper considerably generalize thoseobtained in [9].
Let L be a Schrdinger operator of the form L =-? + V acting on L^2(R^n), n≥3, where the nonnegative potential V belongs to the reverse Hlder class B_q for some q≥n. Let BMO_L(R^n) denote the BMO space associated to ...Let L be a Schrdinger operator of the form L =-? + V acting on L^2(R^n), n≥3, where the nonnegative potential V belongs to the reverse Hlder class B_q for some q≥n. Let BMO_L(R^n) denote the BMO space associated to the Schrdinger operator L on R^n. In this article, we show that for every f ∈ BMO_L(R^n) with compact support, then there exist g ∈ L~∞(R^n) and a finite Carleson measure μ such that f(x) = g(x) + S_(μ,P)(x) with ∥g∥∞ + |||μ|||c≤ C∥f∥BMO_L(R^n), where S_(μ,P)=∫(R_+^(n+1))Pt(x,y)dμ(y, t),and Pt(x, y) is the kernel of the Poisson semigroup {e-^(t(L)^(1/2))}t>0 on L^2(R^n). Conversely, if μ is a Carleson measure, then S_(μ,P) belongs to the space BMO_L(R^n). This extends the result for the classical John-Nirenberg BMO space by Carleson(1976)(see also Garnett and Jones(1982), Uchiyama(1980) and Wilson(1988)) to the BMO setting associated to Schrdinger operators.展开更多
In this paper, we prove that the 2D Navier-Stokes equations possess a global attractor in Hk（Ω,R2） for any k ≥ 1, which attracts any bounded set of Hk（Ω,R2） in the H^k-norm. The result is established by means o...In this paper, we prove that the 2D Navier-Stokes equations possess a global attractor in Hk（Ω,R2） for any k ≥ 1, which attracts any bounded set of Hk（Ω,R2） in the H^k-norm. The result is established by means of an iteration technique and regularity estimates for the linear semigroup of operator, together with a classical existence theorem of global attractor. This extends Ma, Wang and Zhong＇s conclusion.展开更多
In this paper,we are concerned with the stability for a model in the form of system of integro-partial differential equations,which governs the evolution of two competing age-structured populations.The age-specified e...In this paper,we are concerned with the stability for a model in the form of system of integro-partial differential equations,which governs the evolution of two competing age-structured populations.The age-specified environment is incorporated in the vital rates,which displays the hierarchy of ages.By a non-zero fixed-point result,we show the existence of positive equilibria.Some conditions for the stability of steady states are derived by means of semigroup method.Furthermore,numerical experiments are also presented.展开更多
This paper deals with the approximate controllability of semilinear neutral functional differential systems with state-dependent delay. The fractional power theory and α-norm are used to discuss the problem so that t...This paper deals with the approximate controllability of semilinear neutral functional differential systems with state-dependent delay. The fractional power theory and α-norm are used to discuss the problem so that the obtained results can apply to the systems involving derivatives of spatial variables. By methods of functional analysis and semigroup theory, sufficient conditions of approximate controllability are formulated and proved. Finally, an example is provided to illustrate the applications of the obtained results.展开更多
This paper is concerned first with the behaviour of differences T（t） - T（s） near the origin, where （T（t）） is a semigroup of operators on a Banach space, defined either on the positive real line or a sector in ...This paper is concerned first with the behaviour of differences T（t） - T（s） near the origin, where （T（t）） is a semigroup of operators on a Banach space, defined either on the positive real line or a sector in the right half-plane （in which case it is assumed analytic）. For the non-quasinilpotent case extensions of results in the published literature are provided, with best possible constants; in the case of quasinilpotent semigroups on the half-plane, it is shown that, in general, differences such as T（t） -T（2t） have norm approaching 2 near the origin. The techniques given enable one to derive estimates of other functions of the generator of the semigroup; in particular, conditions are given on the derivatives near the origin to guarantee that the semigroup generates a unital algebra and has bounded generator.展开更多
文摘In this paper,we shall exploit the Freud method in the Classical operator approximation theory to im- prove known quantitative estimalions with an emphasis on Calculah' on the generic constants.
基金Supported by the National Natural Science Foundation of China(10861010,11161044)
文摘Let L = --△ ＋ Ⅴ be the SchrSdinger operator on Rd, d ≥ 3, where A is the Laplacian on Rd and V ≠ 0 is a nonnegative function satisfying the reverse HSlder inequality. In this article, the author investigates some properties of the Riesz potential IaL associated with L on the Campanato-type spaces ∧Lβ and the Hardy-type spaces HLP.
基金The NNSF (10171010 and 10201005) of China Major Project of Education Ministry (01061) of China.
文摘In this article, we consider compound matrices and compound operator equations in a Hilbert space. First, we recall some concepts and main results introduced by Muldowney and by Roger Temam. After that we establish the rule of compound matrices in a Hilbert space, and obtain the expression of solution to a compound operator equation by using the method of operator semigroup. Our brief results generalize the corresponding results in a finite space.
文摘Recently in [4], the Jessen＇s type inequality for normalized positive C0-semigroups is obtained. In this note, we present few results of this inequality, yielding Holder＇s Type and Minkowski＇s type inequalities for corresponding semigroup. Moreover, a Dresher＇s type inequality for two-parameter family of means, is also proved.
基金supported by the National Natural Science Foundation Major Program of China(No.12494544)the National Natural Science Foundation General Program of China(No.12171039)+1 种基金the New Cornerstone Science Foundation through the XPLORER PRIZE and Sino-German Center Mobility Programme(No.M-0548)the Shanghai Science and Technology Program(No.21JC1400600)。
文摘The neural operator theory ofers a promising framework for efficiently solving complex systems governed by partial diferential equations(PDEs for short).However,existing neural operators still face significant challenges when applied to spatiotemporal systems that evolve over large time scales,particularly those described by evolution PDEs with time-derivative terms.This paper introduces a novel neural operator designed explicitly for solving evolution equations based on the theory of operator semigroups.The proposed approach is an iterative algorithm where each computational unit,termed the single-step neural operator solver(SSNOS for short),approximates the solution operator for the initial-boundary value problem of semilinear evolution equations over a single time step.The SSNOS consists of both linear and nonlinear components:The linear part approximates the linear operator in the solution map;in contrast,the nonlinear part captures deviations in the solution function caused by the equations nonlinearities.To evaluate the performance of the algorithm,the authors conducted numerical experiments by solving the initial-boundary value problem for a two-dimensional semilinear hyperbolic equation.The experimental results demonstrate that their neural operator can efficiently and accurately approximate the true solution operator.Moreover,the model can achieve a relatively high approximation accuracy with simple pre-training.
文摘We prove that the group of weighted composition operators induced by continuous automorphism groups of the upper half plane U is strongly continuous on the weighted Dirichlet space of U,Dα(U).Further,we investigate when they are isometries on Dα(U).In each case,we determine the semigroup properties while in the case that the induced composition group is an isometry,we apply similarity theory to determine the spectral properties of the group.
基金Sponsored by the National Natural Science Foundation of China(11071177)NSF of Sichuan Science and Technology Department of China(2010JY0057)the NSF of Sichuan Education Department of China(11ZA102)
文摘Existence and regularity of solutions to model for liquid mixture of 3He-4He is considered in this paper. First, it is proved that this system possesses a unique global weak solution in H^1 （Ω, C ×R） by using Galerkin method. Secondly, by using an iteration procedure, regularity estimates for the linear semigroups, it is proved that the model for liquid mixture of 3He-4He has a unique solution in H^k（Ω, C × R） for all k ≥ 1.
文摘In this paper we prove that the initial-boundary value problem for the nonlinear evolution equation ut = △u ＋ λu - u^3 possesses a global attractor in Sobolev space H^k for all k≥0, which attracts any bounded domain of H^k（Ω） in the H^k-norm. This result is established by using an iteration technique and regularity estimates for linear semigroup of operator, which extends the classical result from the case k ∈ [0, 1] to the case k∈ [0, ∞）.
基金Supported by NSFC(11871079)NSFC (11731009)Center for Statistical Science,PKU
文摘In this article, some properties of complex Wiener-It? multiple integrals and complex Ornstein-Uhlenbeck operators and semigroups are obtained. Those include Stroock’s formula, Hu-Meyer formula, Clark-Ocone formula, and the hypercontractivity of complex Ornstein-Uhlenbeck semigroups. As an application, several expansions of the fourth moments of complex Wiener-It? multiple integrals are given.
文摘In this paper we discuss tLhe existence results of the integral solutions to nonlinear evolution inclusion: u' (t) ∈ Au(t) +F(t,u(t)), where A is m-dissipative and F is a set valued map in separable Banach spaces, and extend the relative results in references.
文摘The weighted Sobolev-Lions type spaces W pl,γ（Ω; E0, E） = W pl,γ（Ω; E） ∩ Lp,γ （Ω; E0） are studied, where E0, E are two Banach spaces and E0 is continuously and densely embedded on E. A new concept of capacity of region Ω ∈ Rn in W pl,γ（; E0, E） is introduced. Several conditions in terms of capacity of region Ω and interpolations of E0 and E are found such that ensure the continuity and compactness of embedding operators. In particular, the most regular class of interpolation spaces Eα between E0 and E, depending of α and l, are found such that mixed differential operators Dα are bounded and compact from W pl,γ（Ω; E0, E） to Eα-valued Lp,γ spaces. In applications, the maximal regularity for differential-operator equations with parameters are studied.
文摘In this paper, we discuss the existence and uniqueness of mild solutions of random impulsive abstract neutral partial differential equations in a real separable Hilbert space. The results are obtained by using Leray-Schauder Alternative and Banach Contraction Principle.Finally an example is given to illustrate our problem.
文摘In this paper,the existence,uniqueness and Strichartz type estimates to solutions of multipoint problem for abstract linear and nonlinear wave equations are obtained.The equation includes a linear operator A defined in a Hilbert space H.We obtain the existence,uniqueness regularity properties,and Strichartz type estimates to solutions of a wide class of wave equations which appear in the fields of elastic rod,hydro-dynamical process,plasma,materials science and physics,by choosing the space H and the operator A.
基金Acknowledgements The authors thank the Kavli Institute for Theoretical Physics China and the Morningside Center for Mathematics in Beijing for their hospitality and support. This work was supported by the National Natural Science Foundation of China （Grant Nos. 11201201, 11371178）, the Fundamental Research Funds for the Central Universities （lzujbky-2013-8）, and the National Science Foundation of US （Grant No. DMS 1001855）.
文摘Bracketed words are basic structures both in mathematics （such as Rota-Baxter algebras） and mathematical physics （such as rooted trees） where the locations of the substructures are important. In this paper, we give the classification of the relative locations of two bracketed subwords of a bracketed word in an operated semigroup into the separated, nested, and intersecting cases. We achieve this by establishing a correspondence between relative locations of bracketed words and those of words by applying the concept of Motzkin words which are the algebraic forms of Motzkin paths.
文摘Properties for tensor products of semigroups are considered and the solutions of the equationAC - CB = Q are discussed. Results obtained in this paper considerably generalize thoseobtained in [9].
基金supported by National Natural Science Foundation of China (Grant Nos. 11501583, 11471338, 11622113, 11371378 and 11521101)Australian Research Council Discovery (Grant Nos. DP 140100649 and DP 170101060)+1 种基金Guangdong Natural Science Funds for Distinguished Young Scholar (Grant No. 2016A030306040)Guangdong Special Support Program
文摘Let L be a Schrdinger operator of the form L =-? + V acting on L^2(R^n), n≥3, where the nonnegative potential V belongs to the reverse Hlder class B_q for some q≥n. Let BMO_L(R^n) denote the BMO space associated to the Schrdinger operator L on R^n. In this article, we show that for every f ∈ BMO_L(R^n) with compact support, then there exist g ∈ L~∞(R^n) and a finite Carleson measure μ such that f(x) = g(x) + S_(μ,P)(x) with ∥g∥∞ + |||μ|||c≤ C∥f∥BMO_L(R^n), where S_(μ,P)=∫(R_+^(n+1))Pt(x,y)dμ(y, t),and Pt(x, y) is the kernel of the Poisson semigroup {e-^(t(L)^(1/2))}t>0 on L^2(R^n). Conversely, if μ is a Carleson measure, then S_(μ,P) belongs to the space BMO_L(R^n). This extends the result for the classical John-Nirenberg BMO space by Carleson(1976)(see also Garnett and Jones(1982), Uchiyama(1980) and Wilson(1988)) to the BMO setting associated to Schrdinger operators.
基金Supported by the NSF of China (Nos. 10571142, 10771167)
文摘In this paper, we prove that the 2D Navier-Stokes equations possess a global attractor in Hk（Ω,R2） for any k ≥ 1, which attracts any bounded set of Hk（Ω,R2） in the H^k-norm. The result is established by means of an iteration technique and regularity estimates for the linear semigroup of operator, together with a classical existence theorem of global attractor. This extends Ma, Wang and Zhong＇s conclusion.
基金supported by the National Natural Science Foundation of China(11871185)the Zhejiang Provincial Nat ural Science Foundation of China(LY18A010010).
文摘In this paper,we are concerned with the stability for a model in the form of system of integro-partial differential equations,which governs the evolution of two competing age-structured populations.The age-specified environment is incorporated in the vital rates,which displays the hierarchy of ages.By a non-zero fixed-point result,we show the existence of positive equilibria.Some conditions for the stability of steady states are derived by means of semigroup method.Furthermore,numerical experiments are also presented.
基金supported by the National Natural Science Foundation of China(Nos.11171110,11371087)the Science and Technology Commission of Shanghai Municipality(No.13dz2260400)the Shanghai Leading Academic Discipline Project(No.B407)
文摘This paper deals with the approximate controllability of semilinear neutral functional differential systems with state-dependent delay. The fractional power theory and α-norm are used to discuss the problem so that the obtained results can apply to the systems involving derivatives of spatial variables. By methods of functional analysis and semigroup theory, sufficient conditions of approximate controllability are formulated and proved. Finally, an example is provided to illustrate the applications of the obtained results.
基金Supported by EPSRC (EP/F020341/1)partially supported by the research project AHPIfunded by ANR
文摘This paper is concerned first with the behaviour of differences T（t） - T（s） near the origin, where （T（t）） is a semigroup of operators on a Banach space, defined either on the positive real line or a sector in the right half-plane （in which case it is assumed analytic）. For the non-quasinilpotent case extensions of results in the published literature are provided, with best possible constants; in the case of quasinilpotent semigroups on the half-plane, it is shown that, in general, differences such as T（t） -T（2t） have norm approaching 2 near the origin. The techniques given enable one to derive estimates of other functions of the generator of the semigroup; in particular, conditions are given on the derivatives near the origin to guarantee that the semigroup generates a unital algebra and has bounded generator.
