What # means in math notation?

Question

turingtest · Answer

That depends, but it is usually used to represent the word "number" in common usage, though that is not really math-related.

I can't find any resources on it right now, but I know I've seen it in some very complicated things.

anonymous · Answer

in this book that i'm reading about calculus it says for the given function f(x)=x-2/sqrx-1 + sqrtx-3 must be x-1>0, x-3>0 and sqrtx-1+sqrtx-3 # 0

anonymous · Answer

what the hell is # !!!!!!!!!!!!

anonymous · Answer

weirdest thing!?

turingtest · Answer

Sounds severely like a misprint of an inequality symbol.

anonymous · Answer

$$ \neq $$ ?

anonymous · Answer

its actually an old greek math book so it doesn't really matter

anonymous · Answer

tx for your answers though

anonymous · Answer

http://en.wikipedia.org/wiki/List_of_mathematical_symbols says cardinality :S... which is not the case here....at all...forget it

anonymous · Answer

turing test is right, it used to denote 'number'. For example, #2 means number 2

cristiann · Answer

Since you have the expression sqrx-1 + sqrtx-3 at the denominator, it should mean "nonzero"