Sunday, February 17, 2019

cardinals - Finding a bijection between set of infinite sequences of 0,1,2 and the open interval (0,1)

I've been asked to find bijection between {0,1,2}N, the set of infinite sequences of 0,1 and 2, and the open interval (0,1), and am told that it follows a similar logic to the proof creating a bijection between 10N={0,1,2,3,4,5,6,7,8,9} and the open interval (0,1).



I can find the bijection between 10N={0,1,2,3,4,5,6,7,8,9} and (0,1) by picking some a10N and showing that it converges to some number b(0,1). Noticing that it is possible for two sequences to converge to the same number b(0,1), such as 0.5 and 0.4ˉ9, we create A= "set of sequences with two representations" and B= "numbers with 2 representations". I can then show that these two sets have a bijection between them without much difficulty.



What I do not understand is how to transfer this framework once we no longer have the ability to create an infinite sequence corresponding to any number in (0,1) and I am struggling to find a function that allows me to do so. Any tips would be appreciated.

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