Wednesday, 19 June 2013

elementary set theory - Bijection between [mathbbNto0,1] and [mathcalP(mathbbN)to0,1]

In ZFC (edit : and other axiomatic systems), does there exists a bijection between [N{0,1}] and [P(N){0,1}]?



Extrapolating from https://en.wikipedia.org/wiki/Algebraic_normal_form it seems that there is exactly 22n functions from a set where elements are described with n bits to {0,1}




So by imagining what the limit would be for all possible integer size, it seems that an infinite string of {0,1} is exactly the description of one particular function from N to {0,1}



But then with the same argument, an infinite string of {0,1} would also be the description of exactly one particular function from a subset of N (which also happens to be a function from N to {0,1} in that view expressed here) to {0,1}



Hence i would tend to conclude that [N{0,1}] and [P(N){0,1}] are the same thing ..



What is the view of ZFC (and other axiomatic systems) on the matter, do both set of functions have the same cardinality (which i take is equivalent to ask for the existence of a bijection between the two ) ?



Edit : i would like to extend the questions to other axiomatic systems than ZFC

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