“…It is easy to prove that every linear normed space is a convex metric space with a convex structure W x, y, z; a, b, c = ax + by + cz, for all x, y, z ∈ X and a, b, c ∈ [0, 1] with a + b + c = 1. But there exist some convex metric spaces which can not be embedded into any linear normed spaces (see, Takahashi [5] and, Gunduz and Akbulut [6]).…”