x1 is a binary operator which is commutative in space/under conditions/on (or endowing) set x2; x1 and x2 are each abelian (in different senses).
Denote x1 by "♤"; for any elements x,y in the set of concern, if '♤' is commutative, then x♤y = y♤x, where equality is defined in the space. "Commutative property"/"commutativity" = "ka(m)( )cajni". See also: socni, sezni, dukni, facni.