Compoundation invariance and Bohmian mechanics

The property of fundamental mechanical theories which allow to treat compou nd objects as particles under suitable conditions is considered. It is argu ed that such a property, called compoundation invariance, is a nonreleasabl e property of any mechanical theory not declaring to which elementary const ituents it applies. Compoundation invariance is discussed in the framework of Bohmian mechanics. It is found that standard Bohmian mechanics satisfies the requirement of compoundation invariance, with some reservation is viol ated when additional terms are added to the standard velocity.