If A and B are both countably infinite then prove that is countably inifinite. I was working on this problem with a friend and we know that this means that there is a bijection of both sets, but where do we go from there?
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Originally Posted by andirc5192 If A and B are both countably infinite then prove that is countably inifinite. I was working on this problem with a friend and we know that this means that there is a bijection of both sets, but where do we go from there? Since A and B are both countable we know that there exists a bijection from the integers to the sets. Let and Let let and let Now let Now show that this is both 1-1 and onto
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