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Re:What does 0^0 equal? Why do mathematicians and high schoo... by xyzzyz on Wednesday August 24, 2011 @10:11PM (#2923473)
Please, treat exponentiation just like every other function out there. I don't get the whole limit argument at all. Given any function f: R x R -> R, if it happens that a_n -> a, b_n -> b, but lim f(a_n, b_n) != f(a, b), people just say that f is not continuous in (a, b), and the case is over. However, if f happens to be exponentiation function, people instead argue that f should not be defined in (a, b), forgetting about the fact that the theorem which lets you take a limit of an argument instead of a limit of a function values works only under assumption that f is continuous in a proper point. Instead of noting that there's no contradiction because the assumptions are not satisfied, people just run away from it, declaring 0^0 as undefined.

From this point of view, the whole notion of "indeterminate form" makes just as little sense as distinguishing some arbitrary class of functions and calling them "elementary". Why are some points of discontinuity of some functions more special than other points of discontinuity of other functions? Why sin is more elementary than gamma? Historical heritage of confusion, I guess.

Re:What does 0^0 equal? Why do mathematicians and high schoo... by lotharbot on Wednesday August 24, 2011 @10:41PM (#2923533)
Consider this related case: if you evaluate a limit and you get 0/0, you recognize that you need to do more work to find the actual limit. It could be 1, -1, 0, infinite, etc. depending on how you reached it (say, sin(x)/x versus sin(x)/x^2). The issue is not the continuity of x/x; the issue is whether setting a convention for 0/0 would give you the right value for a limit. Since it doesn't always, we call it "indeterminate".

Similarly, if you're evaluating a limit and you get 0^0 you need to do more work. You can't just stop and say "oh, that's 1". It depends on what function you used to get there -- x^x will give you a different answer from ( e^(-1/x) )^x. Again, it has nothing to do with the continuity of exponentiation. The issue is whether the convention of 0^0=1 is correct in the specific part of mathematics you're working in.

The same argument can be made if you're working in the hyperreals, or if you're working with field axioms -- the convention 0^0 doesn't work in that context.

Please, by all means, use the convention 0^0=1 when it's appropriate. But understand that it's not always appropriate. Not every mathematician works in the particular subschool that you do; not every mathematician is going to find your convention appropriate.

Re:What does 0^0 equal? Why do mathematicians and high schoo... by xyzzyz on Thursday August 25, 2011 @12:47AM (#2923794)
Consider this related case: if you evaluate a limit and you get 0/0

What do you mean by "getting 0/0" in the process of evaluating limits?

The issue is not the continuity of x/x; the issue is whether setting a convention for 0/0 would give you the right value for a limit.

Please, tell me - what is the relation between lim f(a_n) and f(lim a_n) ?