arXiv subjects

Yohei Tsutsui

Publications and source records attributed to Yohei Tsutsui.

5 recordsLinked to original sources

arXiv2024

Fractional medians and their maximal functions

In this article, we introduce the fractional medians, give an expression of the set of all fractional medians in terms of non-increasing rearrangements and then investigate mapping properties of the fractional maximal operators defined by such medians. The maximal operator is a generalization of that in Stromberg. It turns out that our maximal operator is a more smooth operator than the usual fractional maximal operator. Further, we give another proof of the embedding from $BV$ to $L^{n/(n-1),1}$ due to Alvino by using the usual medians.

math.CA↗

arXiv2024

Two-weight inequality for the heat flow and solvability of Hardy-Hénon parabolic equation

In this article, we provide two-weight inequalities for the heat flow on the whole space by applying the sparse domination. For power weights, such inequalities were given by several authors. Owing to the sparse domination, we can treat general weights in Muckenhoupt classes. As a application, we present the local and global existence results for the Hardy-Hénon parabolic equation, which has a potential belonging to a Muckenhoupt class.

math.CA↗

arXiv2018

Remark on the strong solvability of the Navier-Stokes equations in the weak $L^n$ space

The initial value problem of the incompressible Navier-Stokes equations with non-zero forces in $L^{n,\infty}(\mathbb{R}^n)$ is investigated. Even though the Stokes semigroup is not strongly continuous on $L^{n,\infty}(\mathbb{R}^n)$, with the qualitative condition for the external forces, it is clarified that the mild solution of the Naiver-Stokes equations satisfies the differential equations in the topology of $L^{n,\infty}(\mathbb{R}^n)$. Inspired by the conditions for the forces, we characterize the maximal complete subspace in $L^{n,\infty}(\mathbb{R}^n)$ where the Stokes semigroup is strongly continuous at $t=0$. By virtue of this subspace, we also show local well-posedness of the strong solvability of the Cauchy problem without any smallness condition on the initial data in the subspace. Finally, we discuss the uniqueness criterion for the mild solutions in weak Lebesgue spaces by the argument by Brezis.

math.AP↗

arXiv2017

Asymptotic stability of the stationary Navier-Stokes flows in Besov spaces

We discuss the asymptotic stability of stationary solutions to the incompressible Navier-Stokes equations on the whole space in Besov spaces with positive smoothness and low integrability. A critical estimate for the semigroup generated by the Laplacian with a perturbation is main ingredient of the argument.

math.AP↗

arXiv2016

Trace operators on Wiener amalgam spaces

The paper deals with trace operators of Wiener amalgam spaces using frequency-uniform decomposition operators and maximal inequalities, obtaining sharp results. Additionally, we provide the embeddings between standard and anisotropic Wiener amalgam spaces.

math.FA↗