Quote:
Originally Posted by Piwoslaw
"OK, let's use this equation in an example with actual numbers, like a, b, and c."

Yes, as much as possible. That variable/constant distinction is great. Or better when one says "R is a binary relation" or "H is an operator". Even without letters, "constants" such as 0 seem pretty arbitrary. Now I learn the number 0 is just another name for the empty set because of von Neumann ordinals.