Pr\"ufer $\star$--multiplication domains and $\star$--coherence
  The purpose of this paper is to deepen the study of the Pr\"ufer $\star$--multiplication domains, where $\star$ is a semistar operation. For this reason, in Section 2, we introduce the $\star$--domains, as a natural extension of the $v$--domains, where $v$ is the classical Artin's divisorial operation. We investigate their close relation with the Pr\"ufer $\star$--multiplication domains. In particular, in Section 3, we obtain a characterization of Pr\"ufer $\star$--multiplication domains in terms of $\star$--domains satisfying a variety of coherent-like conditions. In Section 4, we extend to the semistar setting the notion of $\texttt{H}$--domain introduced by Glaz and Vasconcelos and we show, among the other results that, in the class of the $\texttt{H}(\star)$--domains, the Pr\"ufer $\star$--multiplication domains coincide with the $\star$--domains. 
Marco Fontana and Giampaolo Picozza