Inverse source problems for positive operators. I: Hypoelliptic diffusion and subdiffusion equations

M Ruzhansky, N Tokmagambetov… - Journal of Inverse and Ill …, 2019 - degruyter.com
A class of inverse problems for restoring the right-hand side of a parabolic equation for a
large class of positive operators with discrete spectrum is considered. The results on …

Very weak solutions of wave equation for Landau Hamiltonian with irregular electromagnetic field

M Ruzhansky, N Tokmagambetov - Letters in Mathematical Physics, 2017 - Springer
In this paper, we study the Cauchy problem for the Landau Hamiltonian wave equation, with
time-dependent irregular (distributional) electromagnetic field and similarly irregular velocity …

Wave equation for operators with discrete spectrum and irregular propagation speed

M Ruzhansky, N Tokmagambetov - Archive for Rational Mechanics and …, 2017 - Springer
Given a Hilbert space HH, we investigate the well-posedness of the Cauchy problem for the
wave equation for operators with a discrete non-negative spectrum acting on H H. We …

On a non–local problem for a multi–term fractional diffusion-wave equation

M Ruzhansky, N Tokmagambetov… - Fractional Calculus and …, 2020 - degruyter.com
This paper deals with the multi-term generalisation of the time-fractional diffusion-wave
equation for general operators with discrete spectrum, as well as for positive hypoelliptic …

Time-fractional discrete diffusion equation for Schrödinger operator

A Dasgupta, SS Mondal, M Ruzhansky… - Fractional Calculus and …, 2024 - Springer
This article aims to investigate the semi-classical analog of the general Caputo-type
diffusion equation with time-dependent diffusion coefficient associated with the discrete …

[HTML][HTML] Wave propagation with irregular dissipation and applications to acoustic problems and shallow waters

JC Muñoz, M Ruzhansky, N Tokmagambetov - Journal de mathematiques …, 2019 - Elsevier
In this paper we consider an acoustic problem of wave propagation through a discontinuous
medium. The problem is reduced to the dissipative wave equation with distributional …

An inverse source problem for pseudo-parabolic equation with Caputo derivative

LD Long, NH Luc, S Tatar, D Baleanu… - Journal of Applied …, 2022 - Springer
In this paper, we consider an inverse source problem for a fractional pseudo-parabolic
equation. We show that the problem is severely ill-posed (in the sense of Hadamard) and …

[HTML][HTML] Nonlinear damped wave equations for the sub-Laplacian on the Heisenberg group and for Rockland operators on graded Lie groups

M Ruzhansky, N Tokmagambetov - Journal of Differential Equations, 2018 - Elsevier
In this paper we study the Cauchy problem for the semilinear damped wave equation for the
sub-Laplacian on the Heisenberg group. In the case of the positive mass, we show the …

Subelliptic pseudo-differential operators and Fourier integral operators on compact Lie groups

D Cardona, M Ruzhansky - arxiv preprint arxiv:2008.09651, 2020 - arxiv.org
In this memoir we extend the theory of global pseudo-differential operators to the setting of
arbitrary sub-Riemannian structures on a compact Lie group. More precisely, given a …

[PDF][PDF] Wave equation with distributional propagation speed and mass term: numerical simulations

A Altybay, M Ruzhansky… - Applied Mathematics E …, 2019 - emis.icm.edu.pl
In this paper we explore numerically the theoretical results of the paper [10], and report on
the numerical study of the Cauchy–Dirichlet problem for the 1D wave equation with …