I considered deleting the post, but this seems more cowardly than just admitting I was wrong. But TIL something!

  • @lemmington_steele
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    511 months ago

    actually you can for each real number you can exhaustively map a uninque number from the interval (0,1) onto it. (there are many such examples, you can find one way by playing around with the function tanx)

    this means these two sets are of the same size by the mathematical definition of cardinality :)

    • @PotatoKat
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      -111 months ago

      You mean integers and real numbers between 0 and 1.

      All real numbers would start at 0, 0.1, 0.001, 0.0001… (a 1:1 match with the set between 0 and 1) all the way to 1, 1.1, 1.01… Etc.

      • @lemmington_steele
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        411 months ago

        no, there aren’t enough integers to map onto the interval (0,1).

        probably the most famous proof for this is Cantor’s diagonalisation argument. though as it usually shows how the cardinality of the naturals is small than this interval, you’ll also need to prove that the cardinality of the integers is the same as that of the naturals too (which is usually seen when you go about constructing the set of integers to begin with)

      • lad
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        fedilink
        311 months ago

        No, ey mean real numbers and real numbers. Any interval of real numbers will have enough numbers to be equivalent to any other (infinite ones included)