Non-abelian group
In mathematics , and specifically in group theory , a non-abelian group , sometimes called a non-commutative group , is a group ( "G" , ∗ ) in which there exists at least one pair of elements "a" and "b" of "G" , such that "a" ∗ "b" ≠ "b" ∗ "a" . 
<triplet> group <subj> group theory <obj> studied by