A reinforcement-depletion urn model: A contiguity case

Abstract

SummaryAn urn contains balls of s different colors. The problem of the reinforcement of a specified color and random depletion of balls has been considered by Bernard (1977, Bull. Math. Biol., 39, 463-470) and Shenton (1981, Bull. Math. Biol., 43, 327-340), (1983, Bull. Math. Biol., 45, 1-9). Here we consider a special relation between a reinforcement and depletion, leading to a hypergeometric distribution.