Lagrange Theorem for polygroups

Abstract

So far, isomorphism theorems in hyperstructure were proved for different structures of polygroups, hyperrings and etc. Inthis paper, the polygroups properties is studied with the introduction of a suitable equivalence relation. We show that the above relationis strongly regular. Our main purpose in the paper is investigating Lagrang theorem and other expressing of isomorphism theorems forpolygroups