So, as you may or may not have known there's an interesting correlation between galaxy brightness and it's color. Basically, the brighter the absolute luminosity of a galaxy the redder it tends to be when compared to galaxies of the same type. I say "tends" because randomness does give the exact result some leeway. I was wondering if anyone had the relationships in "mathspeak" as I call it. I'd be very interested in the equation used to derive and display this.