the noncommuting graph $nabla (g)$ of a group $g$ is asimple graph whose vertex set is the set of noncentral elements of$g$ and the edges of which are the ones connecting twononcommuting elements. we determine here, up to isomorphism, thestructure of any finite nonabeilan group $g$ whose noncommutinggraph is a split graph, that is, a graph whose vertex set can bepartitioned into two sets such t...

Severe range degradation was critically extended in many region of Iran and caused many rangelands were restricted and interwoven with croplands in a complex system. Therefore, rangeland planning and inventory as an isolated activity has become almost impossible. Current landscape planning involves contributions of different social organizations often with different interests and with different...

this article is intended to be a survey on some combinatorial topics in group theory. the bibliography at the end is neither claimed to be exhaustive, nor is it necessarily connected with a reference in the text. i include it as i see it revolves around the concepts which are discussed in the text.

Let [Formula: see text] be a finite group and fixed prime divisor of text]. We prove that if every maximal subgroup is nilpotent, or normal, has text]-order, then (1) solvable; (2) Sylow tower; (3) there exists at most one such neither text]-nilpotent nor text]-closed.