On Meromorphic Functions That Share Four Values

Abstract

In this paper, two results on meromorphic functions sharing four values are obtained. We proved THEOREM 1. Let f and g be two distinct nonconstant meromorphic functions sharing four values. Suppose that two of these values, say a and b, satisfy τ( a) > 4/5 and τ( b) > 4/5. Then f and g share all four values CM. THEOREM 2. Let f and g be two distinct nonconstant meromorphic functions sharing four values, whose cross ratio is equal to − 1. Suppose that two of these values, say a and b, satisfy τ( a) > 2/3 and τ( b) > 2/3. Then f and g share all four values CM.