M. Mojahedfar - Department of Mathematics University of Mazandaran, Babolsar, Iran.
A.A. Talebi - Department of Mathematics University of Mazandaran, Babolsar, Iran.

In this paper, we de ne the concept of level graphs on IVFGs, and intro- duce the notion of [ ; ]􀀀homomorphism, isomorphism, weak isomorphism, and co weakisomorphism of IVFG by [ ; ]􀀀homomorphism. Also, an application of homomorphism of IVFGs has been presented by using coloring-FG. Electricity is one of the discoveriesthat has changed the daily life of everyone on the planet. Because managing electricity usage is very important, therefore, we have tried to determine the most e ective person in an electrical power department based on the performance of its sta .

Interval valued fuzzy set, interval valued fuzzy graph, level graphs, homo- morphism, weak isomorphism, co-weak isomorphism