BOUGARICHE , MeriemBOUAKKAZ , AhlèmeLATRECHE , Abdelkrim2024-12-042024-12-042024http://dspace.univ-skikda.dz:4000/handle/123456789/3627In this work, a fourth-order neutral functional differential equation with a time-varying delay is investigated. With the help of the Krasnoselskii fixed point theorem as well as the Green's functions method and some functional analysis tools, we established some sufficient criteria that ensure the existence of at least one positive periodic solution for the proposed equationenMasters degree thesis