It is as I was taught in college. In mathematics exact definitions are important, but I don't suppose you would appreciate that. Since I never claimed to invent the field of mathematics your snarky comments aren't appreciated.
What I appreciate is character, integrity, and honesty. If you possessed any of those qualities you wouldn't have interpreted my initial post to you as snarky.
Believe me, if I decide to get snarky with you, you'll know it.