Strict refinement property of connected loop-free categories

Abstract

In this paper we study the strict refinement property for connected partial ordersalso known as Hashimoto's Theorem. This property implies that any isomorphismbetween products of irreducible structures is determined is uniquely determinedas a product of isomorphisms between the factors. This refinement implies asort of smallest possible decomposition for such structures. After a brief recallof the necessary notion we prove that Hashimoto's theorem can be extendedto connected loop-free categories, i.e. categories with no non-trivial morphismsendomorphisms. A special case of such categories is the category of connectedcomponents, for concurrent programs without loops.