Abstract :
We consider a finitely branching transition system as a coalgebra for an endofunctor on the category Set of small sets. A map in that category is a functional bisimulation. So, we study the structure of the category of finitely branching transition systems and functional bisimulations by proving general results about the category H-Coalg of H-coalgebras for an endofunctor H on Set. We give conditions under which H-Coalg is complete, cocomplete, symmetric monoidal closed, regular, and has a subobject classifier