Abstract:
The study of finite groups whose prime graphs do not contain triangles is continued. The main result of the given part of the work is the following theorem: if $G$ is a finite non-solvable group whose prime graph does not contain triangles and $S(G)$ is the greatest solvable normal subgroup in $G$ then $|\pi(G)|\leq 8$ and $|\pi(S(G))|\leq 3$. Furthermore, a detailed description of the structure of a group $G$ satisfying the conditions of the theorem in the case when $\pi(S(G))$ contains a number which does not divide the order of the group $G/S(G)$. It is also constructed an example of a finite solvable group with the Fitting length 5 whose prime graph is 4-cycle. This completes the determination of exact bound for the Fitting length of finite solvable groups whose prime graphs do not contain triangles.
Keywords:finite group, non-solvable group, solvable group, fitting length, prime graph.