RE: [math-fun] elliptic mean

<<=RCS << Must a Mean associate? -- Rich

=Dan ...the arithmetic mean fails to associate. Good point. I once had to explain this to a school teacher who was averaging test scores this way.

But what is the Official Definition of "mean" anyway? Looking at mathworld, it would seem that we must have x M y = y M x x min y <= x M y <= x max y ax M ay = a(x M y) Is that it?