Question

Let a be the set of all non-singular matrices over real numbers and let * be the matrix multiplication operator. Then < a, * > is a monoid but not a group < a, * > is a semi group but not a monoid < a, * > is a group but not an abelian group a is closed under * but < a, * > is not a semi group

Answer 1

< a, * > is a group but not an abelian group .

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