How do we determine if the set of rational numbers and the set of all english sentences are countable or not? I had proved it for the set of Integers in graduation. Our instructor at that time told us that there is some special way to prove it for these two sets but he did not say how. :(
How do we determine if the set of rational numbers and the set of all english sentences are countable or not?
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combinatorics
elementary-set-theory
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0Reposted from http://mathoverflow.net/questions/105740/how-do-we-determine-if-the-set-of-rational-numbers-and-the-set-of-all-english-sen as requested. – 2012-08-29