arXiv subjects

Rupak K. Dalai

Publications and source records attributed to Rupak K. Dalai.

3 recordsLinked to original sources

arXiv2026

Pointwise convergence to initial data of heat and Hermite-heat equations in Modulation Spaces

We characterize weighted modulation spaces (data space) for which the heat semigroup $e^{-tL}f$ converges pointwise to the initial data $f$ as time $t$ tends to zero. Here $L$ stands for the standard Laplacian $-Δ$ or Hermite operator $H=-Δ+|x|^2$ on the Euclidean space. This is the first result on pointwise convergence with data in a weighted modulation spaces (which do not coincide with weighted Lebesgue spaces). We also prove that the Hardy-Littlewood maximal operator operates on certain modulation spaces. This may be of independent interest. We have highlighted several open questions that arise naturally from our findings.

math.AP↗

arXiv2025

A unified framework for pointwise convergence to the initial data of heat equations in metric measure spaces

Given a metric measure space $(\mathcal{X}, d, μ)$ satisfying the volume doubling condition, we consider a semigroup $\{S_t\}$ and the associated heat operator. We propose general conditions on the heat kernel so that the solutions of the associated heat equations attain the initial data pointwise. We demonstrate that these conditions are satisfied by a broad class of operators, including the Laplace operators perturbed by a gradient, fractional Laplacian, mixed local-nonlocal operators, Laplacian on Riemannian manifolds, Dunkl Laplacian and many more. In addition, we consider the Laplace operator in $\mathbb{R}^n$ with the Hardy potential and establish a characterization for the pointwise convergence to the initial data. We also prove similar results for the nonhomogeneous equations and showcase an application for the power-type nonlinearities.

math.AP↗

arXiv2024

Pointwise convergence for the heat equation on tori $\mathbb T^n$ and waveguide manifold $\mathbb T^n \times \mathbb R^m$

We completely characterize the weighted Lebesgue spaces on the torus $\mathbb T^n$ and waveguide manifold $\mathbb T^n \times \mathbb R^m$ for which the solutions of the heat equation converge pointwise (as time tends to zero) to the initial data. In the process, we also characterize the weighted Lebesgue spaces for the boundedness of maximal operators on the torus and waveguide manifold, which may be of independent interest.

math.AP↗