报告主题： On mathematical models by (variable-order) time-fractional diffusion equations
报告人：Hong Wang 教授 （Department of Mathematics, University of South Carolina）
报告时间：2019年5月13日（周一）14：00
报告地点：校本部G507
邀请人：李常品
主办部门：理学院数学系
报告摘要：Recently, Stynes et al proved that time-fractional diffusion equations (tFDEs) generate solutions with singularity near the initial time t=0, which makes the error estimates in the literature that were proved under full regularity assumptions of the true solutions inappropriate.From a modeling point of view, the singularities of the solutions to tFDEs at t=0 do not seem physically relevant to the diffusive transport the tFDEs model. The fundamental reason lies between the incompatibility between the nonlocality of tFDEs and the locality of the initial condition.To eliminate the incompatibility, we propose a modified tFDE model in which the fractional order will vary near the time t=0, which naturally leads to variable-order tFDEs. We will also show that variable-order tFDEs occur naturally in applications. Finally, we briefly discuss the mathematical difficulties in the analysis of variable-order tFDEs, since many widely used Laplace transform based techniques do not apply here.
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