This marginalization produces the classical Chinese restaurant process representation (Teh, 2006).
when working with the morphology models we are proposing, we also need to marginalize the different latent forms (stems s and patterns p) that may have given rise to a given word w. we require that the inverse relation of GENERATE is available to compute the marginal base word distribution: Since our approach encodes morphology using FSTs, which are invertible, this poses no problem.