Consider the sequence of powers of an element "g\\in G":
"g, g^2, g^3,\\dots, g^k,\\dots"
Since "G" is finite and "G" contains this sequence, there exist "t, s\\in\\mathbb N, t<s", such that "g^s=g^t". Multiply both part of this equality by "(g^t)^{-1}=g^{-t}". Then "g^{s-t}=e" and "s-t>0". Let "n=s-t\\in\\mathbb N". We conclude that "g^n=e."
Comments
Leave a comment