“…Then, there exists y ∈ Z such that f (y) ≤ f (x); d(x, y) ≤ 1 and f (z) > f (y) − d(y, z) for all y = z. Now, we study generalized metric spaces and their properties, for more details and application, we refer to [7,[14][15][16][17][18][19][20][21][22][23].…”