Goa, Mengistu (PhD)Leikun, Abie2019-10-012023-11-042019-10-012023-11-042018-09-03http://etd.aau.edu.et/handle/123456789/19255This thesis is concerned with Semilinear evolution equations on a bounded Ω n<Rn with boundary conditions. Existence and uniqueness result of classical, mild and strong solutions of the problem is established using Co-Semigroup operator approach, Banach’s contraction principles and application of Schuader’s fixed point theorems apply to Semilinear evolution equations.enThesis