Oscillation of solutions of first order nonlinear delay difference equations

This thesis consists of four chapters. The first chapter is devoted to the introduction section and provide a generel knowledge of literature. In the second chapter, we mention some basic notions and studies so far. Third chapter is devoted to our original results. In the third chapter, new oscillatory conditions are obtained for first order nonlinear delay difference equation given by ∆x(n)+∑_(i=1)^m▒〖p_i (n) f_i (x(τ_i (n))) 〗=0 where {p_i (n)} are sequences of positive real numbers and {τ_i (n)} are sequences of integers and are not necessarily monotone for 1≤i≤m such that n≥0 için τ_i (n)≤n-1, lim┬(n→∞)⁡〖τ_i (n)=∞,〗 1≤i≤m and f_i∈C(R,R) ve x≠0 için xf_i>0,1≤i≤m and forward difference operator is given by ∆x(n)=x(n+1)-x(n) Finally, the discussion and conclusion part is given.