Finite solvable groups whose Gruenberg-Kegel graph has a cut-set
摘要
Let Γ(G) be the Gruenberg-Kegel graph of a finite group G. We prove that if G is solvable and σ is a cut-set for Γ(G), then G has a σ-series of length 5 whose factors are controlled. As a consequence, we prove that if G is a solvable group and Γ(G) has a cut-vertex p, then the Fitting length ℓF(G) of G is bounded and the bound obtained is the best possible. A cut-set is said minimal if it does not contain any other proper subset that is a cut-set for the graph. For a finite solvable group G, we give a geometrical description of Γ(G) when it has minimal cut-set of size 2.