commutator m21k In mathematics, the commutator of two elements g and h of a group G with *, the operator (binary Operation) on G is the element g-1*h-1*g*h, often denoted by [g,h], where g-1 is the inverse of g and h-1 inverse of h. [g, h] is equal to the group's identity if and only if g and h commute, i.e., if and only if g*h = h*g. 041018 ... . iLink:- Group http://mathworld.wolfram.com/Group.html 041018 ... kx21 Definition:- element M_Species of "Observables"... 041018 what's it to you? who go blather from