In this paper, we de ne some new Homomorphism-monotone parameters for hy-pergraphs. Using these parameters, we extend some graph Homomorphism results to hyper-graph case. Also, we present some bounds for some well-known invariants of hypergraphs such as fractional chromatic number, independent numer and some other invariants of hyergraphs, in terms of these parameters.

In this paper we introduce the notion of φ-commutativity for a Banach algebra A, where φ is a continuous Homomorphism on A and study the concept of φ-weak amenability for φ-commutative Banach algebras. We give an example to show that the class of φ-weakly amenable Banach algebras is larger than that of weakly amenable commutative Banach algebras. We characterize φ-weak amenability of φ-commutative Banach algebras and prove some hereditary properties. Moreover we verify some of the previous available results about commutative weakly amenable Banach algebras, for φ-commutative φ-weakly amenable Banach algebras.

The clique polynomial of a graph G is the ordinary generating function of the number of complete subgraphs (cliques) of G. In this paper, we introduce a new vertex-weighted version of these polynomials. We also show that these weighted clique polynomials have always a real root provided that the weights are non-negative real numbers. As an application, we obtain a no-Homomorphism criteria based on the largest real root of our vertex-weighted clique polynomial.

The aim of this paper is to introduce the notion of fuzzy Homomorphism and fuzzy isomorphism between two n-ary hypergroups and to extend the fuzzy results of fundamental equivalence relations to n-ary hypergroups. We study some of their properties and prove the decomposition theorems for fuzzy Homomorphism and fuzzy isomorphism.

Martindale proved that under some conditions every multiplicative isomorphism between two rings is additive. In this paper, we extend this theorem to a larger class of mappings and conclude that every multiplicative ( ;  )􀀀 derivation is additive.