A graph G is called a graphoidal graph if there exists a graph H and a graphoidal cover ψ of H such that G ≅ Ω (H, ψ ). Then the graph G is said to be self-graphoidal if it is isomorphic to one of its graphoidal graphs. ...

Let G be a group, S = {Sᵢ, i ∊ I} a non empty family of (not necessarily distinct) subgroups of infinite index in G and M a Z₂G-module. In [4] the authors defined a homological invariant E*(G, S,M), which is “dual” to the ...

A subgroup H of a finite group G is said to be Hall normally embedded in G if there is a normal subgroup N of G such that H is a Hall subgroup of N. A Schmidt group is a non-nilpotent finite group whose all proper subgroups ...

For any two positive integers m, n, we denote the graph Km,n ⊙ K₁ by G. Ma Ke-Jie proposed a conjecture [9] that pendant edge extension of a complete bipartite graph is a k-graceful graph for k > 2. In this paper we prove ...

Lie algebras are exactly the anticommutative Leibniz algebras. In this article, we conduct a brief analysis of the approach to Leibniz algebras which based on the concept of the anti-center (Lie-center) and antinilpotency ...

Let R ⊆ S be a ring extension, and let A be an R-submodule of S. The saturation of A (in S) by τ is set A[τ] = {x ∈ S : tx ∈ A for some t ∈ τ}, where τ is a multiplicative subset of R. We study properties of saturations ...

An analogue of the Wedderburn Principal Theorem (WPT) is considered for finite-dimensional Jordan superal-gebras A with solvable radical N, N² = 0, and such that A/N ≅ Jospn|2m(F), where F is a field of characteristic zero. ...

The rings considered in this article are nonzero commutative with identity which are not fields. Let R be a ring. We denote the collection of all proper ideals of R by I(R) and the collection I(R)\{(0)} by I(R)*. Recall ...

We continue algebraization of the set of ultrafilters on a metric spaces initiated in [6]. In particular, we define and study metric counterparts of prime, strongly prime and right cancellable ultrafilters from the Stone-Čech ...

The paper deals with methods of constructing square difference labeling of caterpillars and graphs derived from two operations: path union of cycles and disjoint union of stars. The existence of the square difference ...