Friday, November 9, 2018

real analysis - Bijective function need not implies continious




Is there exist a bijective function from [0,1) to R?



I think it will not possible because [0,1) is not isomorphic R



Any hints/solution will be appreciated



thanks u


Answer



Start with the identity on [0,1). Then send 0 to 1/2, 1/2 to 1/3, etc. In the end you get a bijection from [0,1) to (0,1). To get a bijection, in fact, a homeomorphism from (0,1) to R, you can use eg. tan(πxπ/2).




You cannot get a continuous bijection of [0,1) to R though because then the image of (0,1) has to be an interval. But you get R{image of 0}.


No comments:

Post a Comment

analysis - Injection, making bijection

I have injection f:AB and I want to get bijection. Can I just resting codomain to f(A)? I know that every function i...