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We consider the Cauchy problem of the nonlinear heat equation $u_t -\Delta u= u^{b},\ u(0,x)=u_0$, with $b\geq 2$ and $b\in \mathbb{N}$. We prove that initial data $u_0\in \mathcal{S}(\mathbb{R}^{n})$ (the Schwartz class)arbitrarily small…

Analysis of PDEs · Mathematics 2019-02-19 Lorenzo Brandolese , Fernando Cortez

We investigate uniqueness in the inverse problem of reconstructing simultaneously a spacewise conductivity function and a heat source in the parabolic heat equation from the usual conditions of the direct problem and additional information…

Numerical Analysis · Mathematics 2012-10-30 Adriano De Cezaro , B. Tomas Johansson

Continuous data assimilation addresses time-dependent problems with unknown initial conditions by incorporating observations of the solution into a nudging term. For the prototypical heat equation with variable conductivity and the Neumann…

Numerical Analysis · Mathematics 2025-04-01 Vladimir Yushutin

In this paper, we show that bounded weak solutions of the Cauchy problem for general degenerate parabolic equations of the form \begin{equation} \notag u_t \,+\; \mbox{div}\,f(x,t,u) \;=\; \mbox{div}\,(\;\!|\,u\,|^{\alpha} \, \nabla u…

Analysis of PDEs · Mathematics 2019-03-14 Nicolau Matiel Lunardi Diehl , Lucineia Fabris , Juliana Sartori Ziebell

We give large-time asymptotic estimates, both in uniform and $L^1$ norms, for solutions of the Dirichlet heat equation in the complement of a bounded open set of $\mathbb{R}^d$ satisfying certain technical assumptions. We always assume that…

Analysis of PDEs · Mathematics 2025-03-04 José A. Cañizo , Alejandro Gárriz , Fernando Quirós

In this short communication, we announce an algorithmic procedure for constructing non-uniqueness counter-examples of classical solutions to initial-boundary-value problems for a wide class of linear evolution partial differential…

Analysis of PDEs · Mathematics 2025-12-05 Andreas Chatziafratis , Spyridon Kamvissis

We obtain necessary conditions and sufficient conditions on the existence of solutions to the Cauchy problem for a fractional semilinear heat equation with an inhomogeneous term. We identify the strongest spatial singularity of the…

Analysis of PDEs · Mathematics 2019-10-29 Kotaro Hisa , Kazuhiro Ishige , Jin Takahashi

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

We present a systematic study of higher-order Airy-type differential equations providing the explicit form of the solutions, deriving their power series expansions and a probabilistic interpretation. Under suitable convergence hypotheses,…

Probability · Mathematics 2024-10-11 Fabrizio Cinque , Enzo Orsingher

We consider the Cauchy problem for the nonstationary discrete p-Laplacian with inhomogeneous density \r{ho}(x) on an infinite graph which supports the Sobolev inequality. For nonnegative solutions when p > 2, we prove the precise rate of…

Analysis of PDEs · Mathematics 2025-12-25 Alan A. Tedeev

In this work the authors consider the recovery of the point source in the heat equation. The used data is the sparse boundary measurements. The uniqueness theorem of the inverse problem is given. After that, the numerical reconstruction is…

Numerical Analysis · Mathematics 2025-02-06 Qiling Gu , Wenlong Zhang , Zhidong Zhang

In this paper, we consider a linear heat equation with constant coefficients and a single constant delay. Such equations are commonly used to model and study various problems arising in ecology and population biology when describing the…

Analysis of PDEs · Mathematics 2014-01-23 Denys Khusainov , Michael Pokojovy , Elvin Azizbayov

We study the existence of sign-changing solutions to the nonlinear heat equation $\partial _t u = \Delta u + |u|^\alpha u$ on ${\mathbb R}^N $, $N\ge 3$, with $\frac {2} {N-2} < \alpha <\alpha _0$, where $\alpha _0=\frac {4} {N-4+2\sqrt{…

Analysis of PDEs · Mathematics 2020-12-18 Thierry Cazenave , Flávio Dickstein , Ivan Naumkin , Fred B. Weissler

We give a sufficient condition for non-existence of global nonnegative mild solutions of the Cauchy problem for the semilinear heat equation $u' = Lu + f(u)$ in $L^p(X,m)$ for $p \in [1,\infty)$, where $(X,m)$ is a $\sigma$-finite measure…

Analysis of PDEs · Mathematics 2022-05-04 Daniel Lenz , Marcel Schmidt , Ian Zimmermann

In this paper we investigate the asymptotic behavior and decay of the solution of the discrete in time $N$-dimensional heat equation. We give a convergence rate with which the solution tends to the discrete fundamental solution, and the…

Analysis of PDEs · Mathematics 2021-02-23 Edgardo Alvarez , Luciano Abadias

In the standard form of the relativistic heat equation used in astrophysics, information propagates instantaneously, rather than being limited by the speed of light as demanded by relativity. We show how this equation nonetheless follows…

High Energy Astrophysical Phenomena · Physics 2018-07-13 S. K. Lander , N. Andersson

It is well known that generic solutions of the heat equation are not analytic in time in general. Here it is proven that ancient solutions with exponential growth are analytic in time in ${\M} \times (-\infty, 0]$. Here $\M=\R^n$ or is a…

Analysis of PDEs · Mathematics 2019-05-16 Qi S. Zhang

We study the one-dimensional one-phase Stefan problem for the heat equation with a nonlinear boundary condition. We show that all solutions fall into one of three distinct types: global-in-time solutions with exponential decay,…

Analysis of PDEs · Mathematics 2025-10-31 Kensho Araya , Kazuhiro Ishige

Approximate analytical solution of two dimensional problem for stationary Navier-Stokes, continuity and Fourier-Kirchhoff equations describing free convective heat transfer from isothermal surface of half infinite vertical plate is…

Fluid Dynamics · Physics 2012-10-23 Sergey Leble , Witold M. Lewandowski

We study the spatial critical points of the solutions $u=u(x,t)$ of the fractional heat equation. For the Cauchy problem, we show that the origin $0$ satisfies $\nabla_x u(0,t) = 0$ for $t>0$ if and only if the initial data satisfy a…

Analysis of PDEs · Mathematics 2022-12-13 Nicola De Nitti , Shigeru Sakaguchi