Recent content by martijnh

Thank you very much for this lucid explanation, I wish my textbook was that clear! I still wonder about the proof and the practical usefullness of the theorem though! PS: I did not mention \phi in my previous post as I thought Steve suggested I should look at it in a simplified way; Where...

Hmmm if I'd simplify the case and substitute the set of functions by a function that maps \mathbb{N} to \mathbb{N}, and the function inputs f & g by elements from \mathbb{N}... it would basically say something very trivial; a function maps each input to one output, so if the input equals the...

Thank you very much, that certainly helped! So the corrected line of thinking should be; If there are two functions in a set of functions which return the same results for input restricted up to n, then the set of functions yield the same result on either f(n) or g(n). I think I get the...

Hi all, Im doing some self study in set theory, but got kind of stuck with a proof my textbook gives about the so called recursion theorem: What I get from this is: Let \phi be a function that maps the result of a function that maps natural numbers to the set a, to the result of...

Doh *slaps forehead* Thanks!

Homework Statement I'm following an online course on linear algebra where matrix elimination was explained. They showed this for a 3x3 matrix, I wanted to test this with a 2x2 matrix but somehow managed to do something wrong.. I have two equations with 2 unknowns: 2x - y = 0 -x + 2y = 3...

Thanks for clearing that up! So this only holds when you use the same lineair combination for both origins? I got confused because fx both 1/2, 1/2 and 3/4, 1/4 would be valid affine combinations...

Hello there, I have trouble understanding why the coefficients in an affine combination should add up to 1; From the wikipedia article (http://en.wikipedia.org/wiki/Affine_space#Informal_descriptions) it's mentioned that an affine space does not have an origin, so for an translation different...