The Apollo Program used to reveal cities back in the day :P

Well, my reply was actually tongue-in-cheek because of the generality of my definition (used in algebra). I assumed the OP was talking about the integers, not the natural numbers. The integers are an integral domain, so the definition of primality becomes the one for integral domains.

So no, it's not redundant, given the conditions I assumed (I feel I have to say it explicitly this time :-P)

Sorry for the self-reply, but I meant that the "positive" condition is not redundant. The nonzero condition is redundant all right.

Since the OP is talking about "positive" (meaning that there are also "negative" numbers) he's talking about the integers. And since the integers are an integral domain the definition of primality becomes the definition for integral domain:

So it's actually not redundant.

 
Oh, god, what have I become...

Someone should make a game in which you play as an... I don't know, something like a Native American. And, um, maybe something involving killing extraterrestrial life-forms. It would be awesome if you got to kill'em on their ship, actually.

Even better: make it so at the beginning you're in some building and then somehow the whole building ends up on the alien ship.

Oh, and play Don't Fear The Reaper when you're being pulled into the ship.

Oh, wait...

I love Terminal Velocity! There was a game for windows that was called Fury3 which was basically the same thing. It would be nice if they rebooted either.

I haven't played this game, but sounds a lot like Battlezone (the one from 1998). Very fun game, by the way.

We need you to do some recruiting, you make being a mathematician sound fun!

I'd say that if someone is able to postulate things that are contradictory to observed facts, it must be the case that he/she is a logician (just kidding... or not :-P)

Maybe he doesn't mean that they do it with the intent of predicting phenomena, but that they establish the postulates (inspired by something real), then do some work and then produce something that can be used as a model. That does happen (quite often).

Wow, She died just by playing Nethack? No wonder she never attempted it again.

Oh boy, am I glad I didn't make that joke! :-P

If a MÃbius Strip isn't one-sided, could you please give an example of something that is?