Quivers and path semigroups characterized by locality conditions

The notion of locality semigroups was recently introduced with motivation from locality in convex geometry and quantum field theory. We show that there is a natural correspondence between locality sets and quivers which leads to a concrete class of locality semigroups given by the paths of quivers. Further these path semigroups from paths are precisely the free objects in the category of locality semigroups with a rigid condition. This characterization gives a universal property of path algebras and at the same time a combinatorial realization of free rigid locality semigroups.