Abstract
The concepts of M-convex functions and M^〓-convex functions play central roles in the theory of discrete convex analysis which has been applied to mathematical economics. On the other hand, substitutability, which is a key property guaranteeing the existence of a stable matching in generalized stable marriage models, is known as a nice property in mathematical economics. In this paper, we introduce new properties, which are extensions of substitutability, and present new characterizations of M^〓-convex set functions by these properties.
