报告题目：Error analysis for a fractional-derivative parabolic problem on quasi-graded meshes
using barrier functions
报 告 人：孟祥云 北京交通大学
An initial-boundary value problem with a Caputo time derivative of fractional order between 0 and 1 is considered, solutions of which typically exhibit a singular behaviour at an initial time. For this problem, we give a simple and general numerical-stability analysis using barrier functions, which yields sharp pointwise-in-time error bounds on quasi-graded temporal meshes with arbitrary degree of grading. L1-type and Alikhanov-type discretization in time are considered. In particular, those results imply that milder (compared to the optimal) grading yields optimal convergence rates in positive time. Semi-discretizations in time and full discretizations are addressed. The theoretical findings are illustrated by numerical experiments.