A copy of this work was available on the public web and has been preserved in the Wayback Machine. The capture dates from 2017; you can also visit the original URL.
The file type is
We show that the simultaneous existence of a single locally surjective graph homomorphism between a graph G and a connected and finite graph H together with some locally injective homomorphism between the same pair of graphs assures that both homomorphisms are locally bijective. We give a short proof of this assertion which unifies previously known partial results of this form. We utilize the notion of universal cover, and relate its properties to the notion of degree refinement, which was used as a principal tool in other works.doi:10.1016/j.ejc.2006.06.003 fatcat:sducpzmqd5c5fdraxnur6zu2tq