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We study partial data inverse problems for linear and nonlinear parabolic equations with unknown time-dependent coefficients. In particular, we prove uniqueness results for partial data inverse problems for semilinear reaction-diffusion…

Analysis of PDEs · Mathematics 2024-06-04 Ali Feizmohammadi , Yavar Kian , Gunther Uhlmann

We study the well-posedness of a semilinear fractional diffusion equation and formulate an associated inverse problem. We determine fractional power type nonlinearities from the exterior partial measurements of the Dirichlet-to-Neumann map.…

Analysis of PDEs · Mathematics 2022-03-30 Li Li

In this paper we study some cases of time-fractional nonlinear dispersive equations (NDEs) involving Caputo derivatives, by means of the invariant subspace method. This method allows to find exact solutions to nonlinear time-fractional…

Mathematical Physics · Physics 2014-10-30 P. Artale Harris , R. Garra

We discuss the identification of a time-dependent potential in a time-fractional diffusion model from a boundary measurement taken at a single point. Theoretically, we establish a conditional Lipschitz stability for this inverse problem.…

Numerical Analysis · Mathematics 2024-07-23 Siyu Cen , Kwancheol Shin , Zhi Zhou

In this work we investigate an inverse coefficient problem for the one-dimensional subdiffusion model, which involves a Caputo fractional derivative in time. The inverse problem is to determine two coefficients and multiple parameters (the…

Analysis of PDEs · Mathematics 2024-03-19 Siyu Cen , Bangti Jin , Yavar Kian , Eric Soccorsi , Rachid Zarouf , Zhi Zhou

Using the concept of fractional derivatives of Riemann$-$Liouville on time scales, we first introduce right fractional Sobolev spaces and characterize them. Then, we prove the equivalence of some norms in the introduced spaces, and obtain…

Functional Analysis · Mathematics 2022-02-22 Xing Hu , Yongkun Li

A possibility to represent the standard model of fundamental particles covariant derivatives by means of approximate generalized fractional Riemann-Liouville derivatives of multifractal time and space model is shown.

High Energy Physics - Theory · Physics 2007-05-23 L. Ya. Kobelev

The paper considers the initial-boundary value problem for equation $D^\rho_t u(x,t)+ (-\Delta)^\sigma u(x,t)=0$, $\rho\in (0,1)$, $\sigma>0$, in an N-dimensional domain $\Omega$ with a homogeneous Dirichlet condition. The fractional…

Analysis of PDEs · Mathematics 2024-04-17 Ravshan Ashurov , Ilyoskhuja Sulaymonov

We study operators that are generalizations of the classical Riemann-Liouville fractional integral, and of the Riemann-Liouville and Caputo fractional derivatives. A useful formula relating the generalized fractional derivatives is proved,…

Classical Analysis and ODEs · Mathematics 2012-10-29 Tatiana Odzijewicz , Agnieszka B. Malinowska , Delfim F. M. Torres

We study a linear-quadratic optimal control problem involving a parabolic equation with fractional diffusion and Caputo fractional time derivative of orders $s \in (0,1)$ and $\gamma \in (0,1]$, respectively. The spatial fractional…

Optimization and Control · Mathematics 2015-04-02 Harbir Antil , Enrique Otarola , Abner J. Salgado

We use a characterization of the fractional Laplacian as a Dirichlet to Neumann operator for an appropriate differential equation to study its obstacle problem in perforated domains.

Analysis of PDEs · Mathematics 2007-11-15 L. A. Caffarelli , A. Mellet

Time-dependent structures often appear in differential geometry, particularly in the study of non-autonomous differential equations on manifolds. One may study the geodesics associated with a time-dependent Riemannian metric by extremizing…

Differential Geometry · Mathematics 2026-01-21 Xavier Gràcia , Xavier Rivas , Daniel Torres

We show that Liouville-von Neumann approach to quantum mechanical systems, which demands the existence of invariant operators, reproduces the time-dependent variational Gaussian approximation. We find the effective action of the…

High Energy Physics - Theory · Physics 2018-02-14 Hyeong-Chan Kim , Jae Hyung Yee

We show that the fractional wave operator, which is usually studied in the context of hypersingular integrals but had not yet appeared in mathematical physics, can be constructed as the Dirichlet-to-Neumann map associated with the…

Analysis of PDEs · Mathematics 2016-07-18 Alberto Enciso , María del Mar González , Bruno Vergara

We address the inverse problem of identifying a time-dependent source coefficient in a one-dimensional heat equation with a fractional Laplacian subject to Dirichlet boundary conditions and an integral nonlocal data. An a priori estimate is…

Numerical Analysis · Mathematics 2025-11-21 Arshyn Altybay , Niyaz Tokmagambetov , Gulzat Nalzhupbayeva

In this paper, we investigate the inverse problem of determining the right-hand side of a subdiffusion equation with a Caputo time derivative, where the right-hand side depends on both time and certain spatial variables. Similar inverse…

Analysis of PDEs · Mathematics 2025-05-08 R. R. Ashurov , O. T. Mukhiddinova

We investigate the variable-exponent Abel integral equations and corresponding fractional Cauchy problems. The main contributions of the work are enumerated as follows: (i) We develop an approximate inversion technique for variable-exponent…

Classical Analysis and ODEs · Mathematics 2021-10-12 Xiangcheng Zheng

We introduce new fractional operators of variable order on isolated time scales with Mittag-Leffler kernels. This allows a general formulation of a class of fractional variational problems involving variable-order difference operators. Main…

Classical Analysis and ODEs · Mathematics 2019-02-19 Thabet Abdeljawad , Raziye Mert , Delfim F. M. Torres

We study solution techniques for parabolic equations with fractional diffusion and Caputo fractional time derivative, the latter being discretized and analyzed in a general Hilbert space setting. The spatial fractional diffusion is realized…

Numerical Analysis · Mathematics 2015-03-05 Ricardo H. Nochetto , Enrique Otarola , Abner J. Salgado

Employing a phase space which includes the (Riemann-Liouville) fractional derivative of curves evolving on real space, we develop a restricted variational principle for Lagrangian systems yielding the so-called restricted fractional…

Mathematical Physics · Physics 2018-03-01 Fernando Jiménez , Sina Ober-Blöbaum