Quick Gossiping Without Duplicate Transmissions

In this paper we are interested in the combination of Problems (A) and (B). Let f ( n ) denote the minimal number of calls in calling schemes among n persons where everybody hears each gossip exactly once. West [l5] showed that f ( n ) I 2.251 6, if n = 4k, k 2 2. Based on his ideas, we prove f ( n ) I 2.25n 3.5, if n = 4k + 2, k 2 5. On the other hand, West [14] provedf(n) 2 2n 3, if n > 8. The main result of this paper is as follows.