Prove that there are no simple groups of order 4851 or 5145.
- Note that . Suppose is a simple group of order 4851. By Sylow’s Theorem, we have and . Note that does not divide , so that no subgroup of has index less than or equal to 10. In particular, , so that . Let . We have . By Cauchy, there exists a Sylow 11-subgroup . Now is a subgroup, and since 3 does not divide 10 and 11 does not divide 8, by this previous exercise, is abelian. Thus we have . But we also know that , a contradiction.
- Note that . Suppose is a simple group of order 5145. Note that does not divide since the largest power of 7 dividing is . Thus has no proper subgroups of index less than or equal to 20. In particular, from Sylow’s Theorem we have , a contradiction.