Toprakseven, Şuayip2025-07-102025-07-10202208981221https://hdl.handle.net/11494/5747We consider the multi-term time fractional diffusion equation on a bounded convex domain. We analyze the L1 method on a graded mesh in time to compensate for the weak singularity of the solution and a weak Galerkin finite element method in space discretization. The stability analyses are presented for both semi-discrete and fully-discrete schemes and we prove that two schemes are unconditionally stable. Error estimates in L2-norm and a discrete H1 equivalent norm for both schemes are rigorously derived. Further we discuss the optimal spatial order error estimates in L2-norm. Finally, we give some numerical experiments to show the efficiency of the proposed method.eninfo:eu-repo/semantics/embargoedAccessCaputo derivativeGraded meshL1 methodsStabilityThe multi-term time fractional diffusion equationsWeak Galerkin finite-element methodArticle12810812010.1016/j.camwa.2022.10.012s2.0-85141873043Q1