arXiv subjects
Publications and source records attributed to Biqiang Zhao.
In this paper, we study the semilinear elliptic equation and inequality on Sasakian manifolds. First, we obtain Liouville theorems for the equation $Δ_b u+F(u)=0$ based on a generalized Jerison-Lee's formula. Next, we prove the nonexistence of positive weak solutions to the inequality $Δ_b u+F(u)\leq 0 $ under the volume estimate.
In this paper, we consider the inequality $Δ_pu+Δ_qu+u^s|\nabla u|^t\leq 0$ on geodesically complete noncompact Riemannian manifolds. By a test function argument, we establish Liouville-type theorems under the upper bound of volume of geodesic ball. In the Euclidean space $\mathbb{R}^n$, we obtain new nonexistence results which extend the result of Bhakta-Biswas-Filippucci \cite{BBF}. In particular, we have addressed the influence of the higher order term for $s<0$. At last, we present some examples to illustrate sharpness in some cases.
In this paper, we establish Liouville-type theorems for parabolic differential inequalities with $(p,q)-$Laplacian operator on Riemannian manifolds. By a test function argument, we establish nonexistence results under suitable weighted volume growth assumptions involving potential. In particular, we can obtain nonexistence results for a wider class of parabolic inequalities.
In this paper, we study the CR Yamabe type equation \begin{align} Δ_b u+F(u)=0 \nonumber \end{align} on complete noncompact $(2n+1)$-dimensional Sasakian manifolds with nonnegative curvature. Under some assumptions, we prove a rigidity result, that is, the manifold is CR isometric to Heisenberg group $\mathbb{H}^n$. The proofs are based on the Jerison-Lee's differential identity combining with integral estimates.
In this paper, we are concerned with differential inequalities with $(p,q)$-Laplacian operator on Riemannian manifolds. Using a test function argument, we establish Liouville-type theorems under the manifold's geometry and the potential's behavior at infinity.
In this paper, we study the quasilinear inequality $ Δ_m u+f(u)\leq 0$ on a complete Riemannian manifold, where \begin{align*} m>1,α>m-1 \quad and \quad f(t)> 0,αf(t)-tf^{'}(t)\geq 0, \forall t>0. \end{align*} If for some point $x_0$ and large enough $r$, \begin{align*} vol B_r(x_0)\leq C r^p ln^q r, \end{align*} where $p=\frac{mα}{α-(m-1)},q=\frac{m-1}{α-(m-1)}$ and $B_r(x_0) $ is a geodesic ball of radius $r$ centered at $x_0$, then the inequality possesses no positive weak solution. This generalizes the result in \cite{AS,Sun}.
In this paper, we consider maps from pseudo-Hermitian manifolds to Kähler manifolds and introduce partial energy functionals for these maps. First, we obtain a foliated Lichnerowicz type result on general pseudo-Hermitian manifolds, which generalizes a related result on Sasakian manifolds in \cite{SSZ2013holomorphic}. Next, we investigate critical maps of the partial energy functionals, which are referred to as $\overline{\partial }_{b}$-harmonic maps and $\partial _{b}$-harmonic maps. We give a foliated result for both $\overline{\partial }_{b}$- and $\partial _{b}$-harmonic maps, generalizing a foliated result of Petit \cite{Pet2002harmonic} for harmonic maps. Then we are able to generalize Siu's holomorphicity result for harmonic maps \cite{Siu1980rigid} to the case for $\overline{\partial }_{b}$- and $\partial _{b}$-harmonic maps.
In this paper, we derive the gradient estimates for the positive solutions of the equation $Δ_b u + au^{p+1} = 0$ on complete noncompact pseudo-Hermitian manifolds, where $a > 0$ and $p \leq 0$ or $a < 0$ and $p > 0$ are two constants. As an application, we will obtain a Liouville-type theorem when the manifolds are Sasakian-type with nonnegative pseudo-Hermitian Ricci curvature.
In this paper, we derive local and global Li-Yau type gradient estimates for the positive solutions of the CR heat equation on complete noncompact pseudo-Hermitian manifolds. As applications of the gradient estimates, we give a Harnack inequality for the positive solutions of the CR heat equation, and then obtain an upper bound estimate for the corresponding heat kernel.