Finite Groups in Which Number of Non-Subnormal Non-Nilpotent Proper Subgroups of Even Order Is Not Greater Than 21
As a further study of the influence of quantitative property of special subgroups on the solvability of finite groups,we prove that if a non-solvable group G has at most 21 non-subnormal non-nilpotent subgroups of even or-der,G must be isomorphic to the alternating group A5 or the special linear group SL2(5).
even ordernon-nilpotent proper subgroupsolvable groupnon-solvable group