Y.S.Han Finite fields such that a*a'=a *a=e. a and a'are inverse to each other. A group G is called to be commutative if its binary operation also satisfies the following condition:for any a and b in G, a*b=b*a. School of Electrical Engineering Intelligentization,Dongguan University of TechnologyY. S. Han Finite fields 2 such that a ∗ a ′ = a ′ ∗ a = e. a and a ′ are inverse to each other. • A group G is called to be commutative if its binary operation ∗ also satisfies the following condition: for any a and b in G, a ∗ b = b ∗ a. School of Electrical Engineering & Intelligentization, Dongguan University of Technology