Initial-boundary value and inverse problems for subdiffusion equations in ℝ^N
Abstract
An initial-boundary value problem for a subdiffusion equation with an elliptic operator A(D) in R N is considered. The existence and uniqueness theorems for a solution of this problem are proved by the Fourier method. Considering the order of the Caputo time-fractional derivative as an unknown parameter, the corresponding inverse problem of determining this order is studied. It is proved, that the Fourier transform of the solution ( ,t) at a fixed time instance recovers uniquely the unknown parameter. Further, a similar initial-boundary value problem is investigated in the case when operator A(D) is replaced by its power A . Finally, the existence and uniqueness theorems for a solution of the inverse problem of determining both the orders of fractional derivatives with respect to time and the degree are proved. We also note that when solving the inverse problems, a decrease in the parameter of the Mittag-Leffler functions E has been proved.