Odd-order and ambivalent implies trivial

From Groupprops

Statement

Suppose is an Odd-order group (?) (i.e., a finite group of odd order) that is also an Ambivalent group (?): every element is conjugate to its inverse. Then, is the trivial group.

Facts used

  1. Order of element divides order of group

Proof

Suppose has odd order, is ambivalent, and is nontrivial. Then, there exists a non-identity element in . By fact (1), has odd order, so .

Since is ambivalent, there exists such that . Then, , so and commute. Again by fact (1), has odd order, so . Since commutes with , it must commute with all elements in , and hence with . Thus, . This forces , a contradiction.