“…A double sequence x = (x mn ) in X is said to be I * 2 -Cauchy sequence if there exists a set M ∈ F (I 2 ) (i.e., H = N × N\M ∈ I 2 ) such that for each ε > 0 and for all (m, n), (s, t) ∈ M, x mn − x st , z < ε, for each nonzero z in X, where m, n, s, t > k 0 = k 0 (ε) ∈ N. In this case we write lim m,n,s,t→∞ x mn − x st , z = 0. Now, we begin with quoting the following lemmas due to Sarabadan et al [24] and Dündar, Sever [5] which are needed throughout the paper.…”