[math-fun] harmonic sum?

I blurted

What is the conventional name for 1/(1/x+1/y)? (Twice the harmonic mean.) Oops, that's half the harmonic mean.

D Kephart to JPropp

As you might guess, I'm not just thinking this up [...] papers by Lila Kari, et al, Natasha, Kalpana Mahalingam, and myself.

I'd've guessed he *was* thinking this up! As Paul Harvey always said, it's not one world. --rwg hesperinos <-> shore snipe <-> horse penis agnolotti <-> giant tool