Ramsey numbers in octahedron graphs

The octahedron Ramsey number r(O) = r(O)(G(1),....G(t)) is introduced as the smallest n such that any t-coloring of the edges of the octahedron graph O-n =K-2n - nK(2) contains for some i a subgraph G(i) of color i. With r = r(G(i),..., G(t)) denoting the classical Ramsey number, ro is between r/2 and r. If all G(i)'s are complete, then r(O) = r. If all G(i)'s are certain stars, then r(O) = [r/2]. For all G(i) with at most four vertices, all values r(O)(G(1),G(2)) are listed. (C) 2001 Elsevier Science B.V. All rights reserved.