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We derive an adaptation of Li & Yau estimates for positive solutions of semilinear heat equations on Riemannian manifolds with nonnegative Ricci tensor. We then apply these estimates to obtain a Harnack inequality and to discuss…

Analysis of PDEs · Mathematics 2022-01-10 Daniele Castorina , Giovanni Catino , Carlo Mantegazza

This paper presents two observability inequalities for the heat equation over $\Omega\times(0,T)$. In the first one, the observation is from a subset of positive measure in $\Omega\times(0,T)$, while in the second, the observation is from a…

Analysis of PDEs · Mathematics 2013-06-13 J. Apraiz , L. Escauriaza , G. Wang , C. Zhang

We prove an inequality of H\"older type traducing the unique continuation property at one time for the heat equation with a potential and Neumann boundary condition. The main feature of the proof is to overcome the propagation of smallness…

Analysis of PDEs · Mathematics 2021-05-28 Rémi Buffe , Kim Dang Phung

In this paper we investigate on a new strategy combining the logarithmic convexity (or frequency function) and the Carleman commutator to obtain an observation estimate at one time for the heat equation in a bounded domain. We also consider…

Analysis of PDEs · Mathematics 2018-02-19 Kim Dang Phung

We study the existence of solutions to the fractional semilinear heat equation with a singular inhomogeneous term. For this aim, we establish decay estimates of the fractional heat semigroup in several uniformly local Zygumnd spaces.…

Analysis of PDEs · Mathematics 2026-01-14 Kazuhiro Ishige , Tatsuki Kawakami , Ryo Takada

This paper studies the sampling observability for the heat equations with memory in the lower-order term, where the observation is conducted at a finite number of time instants and on a small open subset at each time instant. We present a…

Optimization and Control · Mathematics 2024-11-22 Lingying Ma , Gengsheng Wang , Yubiao Zhang

In this paper, we study quantitative spatial analytic bounds and unique continuation inequalities of solutions for fractional heat equations with an analytic lower order term on the whole space. At first, we show that the solution has a…

Analysis of PDEs · Mathematics 2021-08-24 Ming Wang , Can Zhang

This paper studies connections among observable sets, the observability inequality, the H\"{o}lder-type interpolation inequality and the spectral inequality for the heat equation in $\mathbb R^n$. We present a characteristic of observable…

Optimization and Control · Mathematics 2017-11-29 Gengsheng Wang , Ming Wang , Can Zhang , Yubiao Zhang

We consider the homogenization of a semilinear heat equation with vanishing viscosity and with oscillating positive potential depending on $u/\varepsilon$. According to the rate between the frequency of oscillations in the potential and the…

Analysis of PDEs · Mathematics 2016-07-12 Annalisa Cesaroni , Nicolas Dirr , Matteo Novaga

We derive a matrix version of Li \& Yau--type estimates for positive solutions of semilinear heat equations on Riemannian manifolds with nonnegative sectional curvatures and parallel Ricci tensor, similarly to what R.~Hamilton did…

Analysis of PDEs · Mathematics 2021-07-30 Giacomo Ascione , Daniele Castorina , Giovanni Catino , Carlo Mantegazza

This paper presents a complete analysis of the observability property of heat equations with time-dependent real analytic memory kernels. More precisely, we characterize the geometry of the space-time measurable observation sets ensuring…

Optimization and Control · Mathematics 2024-11-22 Gengsheng Wang , Yubiao Zhang , Enrique Zuazua

The problem of obtaining necessary and sufficient conditions for local existence of non-negative solutions in Lebesgue spaces for semilinear heat equations having monotonically increasing source term $f$ has only recently been resolved…

Analysis of PDEs · Mathematics 2020-05-12 Robert Laister , Mikolaj Sierzega

In this paper, we prove some pointwise comparison results between the solutions of some second-order semilinear elliptic equations in a domain $\Omega$ of $\R^n$ and the solutions of some radially symmetric equations in the equimeasurable…

Analysis of PDEs · Mathematics 2014-04-04 François Hamel , Emmanuel Russ

In this paper, we establish the equivalence of minimal time and minimal norm control problems for semilinear heat equations in which the controls are distributed internally in an open subset of the state domain. As an application, the…

Optimization and Control · Mathematics 2014-04-10 Huaiqiang Yu

A semilinear heat equation $u_{t}=\Delta u+f(u)$ with nonnegative initial data in a subset of $L^{1}(\Omega)$ is considered under the assumption that $f$ is nonnegative and nondecreasing and $\Omega\subseteq \R^{n}$. A simple technique for…

Analysis of PDEs · Mathematics 2012-01-31 James C. Robinson , Mikolaj Sierzega

This study aims to present the error and numerical blow up analyses of a finite element method for computing the radially symmetric solutions of semilinear heat equations. In particular, this study establishes optimal order error estimates…

Numerical Analysis · Mathematics 2019-08-28 Toru Nakanishi , Norikazu Saito

Let $G=(V,E)$ be a locally finite connected weighted graph, and $\Omega$ be an unbounded subset of $V$. Using Rothe's method, we study the existence of solutions for the semilinear heat equation $\partial_tu+|u|^{p-1}\cdot u=\Delta…

Analysis of PDEs · Mathematics 2021-08-31 Yong Lin , Yuanyuan Xie

We establish sharp higher-order heat estimates with complete bound on the noncommutative tori \(\mathbb{T}_{\theta}^{n}\) and show the optimality in the small-time order. As an application in polynomial semilinear heat equations on…

Analysis of PDEs · Mathematics 2026-05-26 Fulin Yang , Zhipeng Yang

Blow up in a one-dimensional semilinear heat equation is studied using a combination of numerical and analytical tools. The focus is on problems periodic in the space variable and starting out from a nearly flat, positive initial condition.…

Analysis of PDEs · Mathematics 2023-02-22 Marco Fasondini , John R. King , J. A. C. Weideman

The local and global existence of the Cauchy problem for semilinear heat equations with small data is studied in the weighted $L^\infty (\mathbb R^n)$ framework by a simple contraction argument. The contraction argument is based on a…

Analysis of PDEs · Mathematics 2018-04-26 Kazumasa Fujiwara , Vladimir Georgiev , Tohru Ozawa
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