A Species Sampling Model with Finitely many Types

TL;DR

This paper introduces a new species sampling model with finitely many types, characterized by a simple updating rule and a power-like distribution for the number of types, enhancing the understanding of exchangeable partitions.

Contribution

It presents a novel exchangeable partition model with a finite number of types and a straightforward updating mechanism, extending the Dirichlet species-sampling framework.

Findings

Derived a power-like distribution for the number of types.

Introduced a simple updating rule for the partition model.

Connected the model to a randomized Dirichlet species-sampling process.

Abstract

A two-parameter family of exchangeable partitions with a simple updating rule is introduced. The partition is identified with a randomized version of a standard symmetric Dirichlet species-sampling model with finitely many types. A power-like distribution for the number of types is derived.