In this paper,we investigate subelliptic harmonic maps with a potential from noncompact complete sub-Riemannian manifolds corresponding to totally geodesic Riemannian foliations.Under some suitable conditions,we give ...In this paper,we investigate subelliptic harmonic maps with a potential from noncompact complete sub-Riemannian manifolds corresponding to totally geodesic Riemannian foliations.Under some suitable conditions,we give the gradient estimates of these maps and establish a Liouville type result.展开更多
We prove that if u is a weak solution of the d dimensional fractional Navier-Stokes equations for some initial data u0, and if u belongs to path space p=Lq（0,T;Br p,∞） or P L1（0, T;B1 ∞,∞）, then u is unique in...We prove that if u is a weak solution of the d dimensional fractional Navier-Stokes equations for some initial data u0, and if u belongs to path space p=Lq（0,T;Br p,∞） or P L1（0, T;B1 ∞,∞）, then u is unique in the class of weak solutions when α〉 1. The main tools are Bony decomposition and Fourier localization technique. The results generalize and improve many recent known results.展开更多
We aim to find the eigenvalues and eigenfunctions of the barrier potential case for Strum-Liouville operator on the finite interval [0,π] when λ > 0. Generally, the eigenvalue problem for the Sturm-Liouville oper...We aim to find the eigenvalues and eigenfunctions of the barrier potential case for Strum-Liouville operator on the finite interval [0,π] when λ > 0. Generally, the eigenvalue problem for the Sturm-Liouville operator is often solved by using integral equations, which are sometimes complex to solve, and difficulties may arise in computing the boundary values. Considering the said complexity, we have successfully developed a technique to give the asymptotic formulae of the eigenvalue and the eigenfunction for Sturm-Liouville operator with barrier potential. The results are of significant interest in the field of quantum mechanics and atomic systems to observe discrete energy levels.展开更多
Harmonic maps with potential from complete manifolds are considered. This is a new kind of maps more general than the usual harmonic maps relating to many interesting problems such as equilibrium system of ferromagnet...Harmonic maps with potential from complete manifolds are considered. This is a new kind of maps more general than the usual harmonic maps relating to many interesting problems such as equilibrium system of ferromagnetic spin chain and Neumann motion. Aiming at the general properties, the author derives basic gradient estimates and then Liouville type results for these maps, which are interesting in constrast to those of the usual harmonic maps for the presence of potentials.展开更多
In this paper we propose and analyze a second order accurate numericalscheme for the Cahn-Hilliard equation with logarithmic Flory Huggins energy potential. A modified Crank-Nicolson approximation is applied to the l...In this paper we propose and analyze a second order accurate numericalscheme for the Cahn-Hilliard equation with logarithmic Flory Huggins energy potential. A modified Crank-Nicolson approximation is applied to the logarithmic nonlinear term, while the expansive term is updated by an explicit second order AdamsBashforth extrapolation, and an alternate temporal stencil is used for the surface diffusion term. A nonlinear artificial regularization term is added in the numerical scheme,which ensures the positivity-preserving property, i.e., the numerical value of the phasevariable is always between -1 and 1 at a point-wise level. Furthermore, an unconditional energy stability of the numerical scheme is derived, leveraging the special formof the logarithmic approximation term. In addition, an optimal rate convergence estimate is provided for the proposed numerical scheme, with the help of linearizedstability analysis. A few numerical results, including both the constant-mobility andsolution-dependent mobility flows, are presented to validate the robustness of the proposed numerical scheme.展开更多
Let Ω be a bounded convex domain in Rn(n≥3) and G(x,y) be the Green function of the Laplace operator -△on Ω Let hPT(Ω) = {f∈D'(Ω) : (?)F ∈ hP(Rn), s.t. F|Ω = f}, by the atom characterization of Local Hard...Let Ω be a bounded convex domain in Rn(n≥3) and G(x,y) be the Green function of the Laplace operator -△on Ω Let hPT(Ω) = {f∈D'(Ω) : (?)F ∈ hP(Rn), s.t. F|Ω = f}, by the atom characterization of Local Hardy spaces in a bounded Lipschitz domain, the bound of f Ω(?)2(Gf) for every f ∈hPr(Ω) is obtained, where n/(n + 1) <p≤1.展开更多
Based on the endpoint Strichartz estimates for the fourth order SchrSdinger equation with potentials for n ≥ 5 by [Feng, H., Softer, A., Yao, X.： Decay estimates and Strichartz estimates of the fourth-order Schr6din...Based on the endpoint Strichartz estimates for the fourth order SchrSdinger equation with potentials for n ≥ 5 by [Feng, H., Softer, A., Yao, X.： Decay estimates and Strichartz estimates of the fourth-order Schr6dinger operator. J. Funct. Anal., 274, 605-658 （2018）], in this paper, the authors further derive Strichartz type estimates with gain of derivatives similar to the one in [Pausader, B.： The cubic fourth-order Schr6dinger equation. J. Funct. Anal., 256, 2473-2517 （2009）]. As their applications, we combine the classical Morawetz estimate and the interaction Morawetz estimate to establish scattering theory in the energy space for the defocusing fourth order NLS with potentials and pure power nonlinearity 1 ＋ 8/n〈 p 〈 1 ＋ 8/n-4 in dimensions n ≥ 7. n展开更多
In this paper,quasi-almost-Einstein metrics on complete manifolds are studied.Two examples are given and several formulas are established.With the help of these formulas,the author proves rigid results on compact or n...In this paper,quasi-almost-Einstein metrics on complete manifolds are studied.Two examples are given and several formulas are established.With the help of these formulas,the author proves rigid results on compact or noncompact manifolds,in which some basic tools,such as the weighted volume comparison theorem and the weak maximum principle at infinity,are used.A lower bound estimate for the scalar curvature is also obtained.展开更多
In this paper, we have studied the separation for the biharmonic Laplace-Beltrami differential operatorAu（x） = -△△u（x） ＋ V（x）u（x）,for all x ∈ R^n, in the Hilbert space H = L2（R^n,H1） with the operator po...In this paper, we have studied the separation for the biharmonic Laplace-Beltrami differential operatorAu（x） = -△△u（x） ＋ V（x）u（x）,for all x ∈ R^n, in the Hilbert space H = L2（R^n,H1） with the operator potential V（x） ∈ C^1 （R^n, L （H1） ）, where L （H1 ） is the space of all bounded linear operators on the Hilbert space H1, while AAu is the biharmonic differential operator and△u=-∑i,j=1^n 1/√detg δ/δxi[√detgg-1（x）δu/δxj]is the Laplace-Beltrami differential operator in R^n. Here g（x） = （gij（x）） is the Riemannian matrix, while g^-1 （x） is the inverse of the matrix g（x）. Moreover, we have studied the existence and uniqueness Theorem for the solution of the non-homogeneous biharmonic Laplace-Beltrami differential equation Au = - △△u ＋ V（x） u （x） = f（x） in the Hilbert space H where f（x） ∈ H as an application of the separation approach.展开更多
文摘In this paper,we investigate subelliptic harmonic maps with a potential from noncompact complete sub-Riemannian manifolds corresponding to totally geodesic Riemannian foliations.Under some suitable conditions,we give the gradient estimates of these maps and establish a Liouville type result.
基金The authors would like to thank the referees very much for their careful reading and their very instructive suggestions which improve this paper greatly. This work was supported in part by the National Natural Science Foundation of China （Grant Nos. 11371057, 11261051, 11161042） and the Specialized Research Fund for the Doctoral Program of Higher Education （Grant No. 20130003110003）.
文摘We prove that if u is a weak solution of the d dimensional fractional Navier-Stokes equations for some initial data u0, and if u belongs to path space p=Lq（0,T;Br p,∞） or P L1（0, T;B1 ∞,∞）, then u is unique in the class of weak solutions when α〉 1. The main tools are Bony decomposition and Fourier localization technique. The results generalize and improve many recent known results.
文摘We aim to find the eigenvalues and eigenfunctions of the barrier potential case for Strum-Liouville operator on the finite interval [0,π] when λ > 0. Generally, the eigenvalue problem for the Sturm-Liouville operator is often solved by using integral equations, which are sometimes complex to solve, and difficulties may arise in computing the boundary values. Considering the said complexity, we have successfully developed a technique to give the asymptotic formulae of the eigenvalue and the eigenfunction for Sturm-Liouville operator with barrier potential. The results are of significant interest in the field of quantum mechanics and atomic systems to observe discrete energy levels.
文摘Harmonic maps with potential from complete manifolds are considered. This is a new kind of maps more general than the usual harmonic maps relating to many interesting problems such as equilibrium system of ferromagnetic spin chain and Neumann motion. Aiming at the general properties, the author derives basic gradient estimates and then Liouville type results for these maps, which are interesting in constrast to those of the usual harmonic maps for the presence of potentials.
基金This work is supported in part by the grants NSFC 12071090(W.Chen)NSF DMS-2012669(C.Wang)+2 种基金NSFC 11871159Guangdong Provincial Key Laboratory for Computational Science and Material Design 2019B030301001(X.Wang)NSF DMS-1719854,DMS-2012634(S.Wise).C.Wang also thanks the Key Laboratory of Mathematics for Nonlinear Sciences,Fudan University,for the support.
文摘In this paper we propose and analyze a second order accurate numericalscheme for the Cahn-Hilliard equation with logarithmic Flory Huggins energy potential. A modified Crank-Nicolson approximation is applied to the logarithmic nonlinear term, while the expansive term is updated by an explicit second order AdamsBashforth extrapolation, and an alternate temporal stencil is used for the surface diffusion term. A nonlinear artificial regularization term is added in the numerical scheme,which ensures the positivity-preserving property, i.e., the numerical value of the phasevariable is always between -1 and 1 at a point-wise level. Furthermore, an unconditional energy stability of the numerical scheme is derived, leveraging the special formof the logarithmic approximation term. In addition, an optimal rate convergence estimate is provided for the proposed numerical scheme, with the help of linearizedstability analysis. A few numerical results, including both the constant-mobility andsolution-dependent mobility flows, are presented to validate the robustness of the proposed numerical scheme.
文摘Let Ω be a bounded convex domain in Rn(n≥3) and G(x,y) be the Green function of the Laplace operator -△on Ω Let hPT(Ω) = {f∈D'(Ω) : (?)F ∈ hP(Rn), s.t. F|Ω = f}, by the atom characterization of Local Hardy spaces in a bounded Lipschitz domain, the bound of f Ω(?)2(Gf) for every f ∈hPr(Ω) is obtained, where n/(n + 1) <p≤1.
基金supported by the China National Science Foundation(Grant Nos.11371158 and 11771165)the second author is supported by the China National Science Foundation(Grant Nos.11101172 and 11571131)
文摘Based on the endpoint Strichartz estimates for the fourth order SchrSdinger equation with potentials for n ≥ 5 by [Feng, H., Softer, A., Yao, X.： Decay estimates and Strichartz estimates of the fourth-order Schr6dinger operator. J. Funct. Anal., 274, 605-658 （2018）], in this paper, the authors further derive Strichartz type estimates with gain of derivatives similar to the one in [Pausader, B.： The cubic fourth-order Schr6dinger equation. J. Funct. Anal., 256, 2473-2517 （2009）]. As their applications, we combine the classical Morawetz estimate and the interaction Morawetz estimate to establish scattering theory in the energy space for the defocusing fourth order NLS with potentials and pure power nonlinearity 1 ＋ 8/n〈 p 〈 1 ＋ 8/n-4 in dimensions n ≥ 7. n
基金Project supported by the National Natural Science Foundation of China(Nos.10971066,11171254)
文摘In this paper,quasi-almost-Einstein metrics on complete manifolds are studied.Two examples are given and several formulas are established.With the help of these formulas,the author proves rigid results on compact or noncompact manifolds,in which some basic tools,such as the weighted volume comparison theorem and the weak maximum principle at infinity,are used.A lower bound estimate for the scalar curvature is also obtained.
文摘In this paper, we have studied the separation for the biharmonic Laplace-Beltrami differential operatorAu（x） = -△△u（x） ＋ V（x）u（x）,for all x ∈ R^n, in the Hilbert space H = L2（R^n,H1） with the operator potential V（x） ∈ C^1 （R^n, L （H1） ）, where L （H1 ） is the space of all bounded linear operators on the Hilbert space H1, while AAu is the biharmonic differential operator and△u=-∑i,j=1^n 1/√detg δ/δxi[√detgg-1（x）δu/δxj]is the Laplace-Beltrami differential operator in R^n. Here g（x） = （gij（x）） is the Riemannian matrix, while g^-1 （x） is the inverse of the matrix g（x）. Moreover, we have studied the existence and uniqueness Theorem for the solution of the non-homogeneous biharmonic Laplace-Beltrami differential equation Au = - △△u ＋ V（x） u （x） = f（x） in the Hilbert space H where f（x） ∈ H as an application of the separation approach.
