I know that Bourbaki were the first who used the word 'bijection', but one-to one functions were for sure used before them. So do you aware of the earliest examples of one-to-one correspondences?

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    $\begingroup$ "If I should ask further how many squares there are, one might replay truly that there are as many as the corresponding number of roots, since every square has its own root and every root its own square, while no square has more than one root and no root more than one square." Galileo, Two New Sciences (1638). Wouldn't be surprised if there were earlier uses, though. $\endgroup$
    – Michael E2
    Commented Sep 10, 2023 at 1:34
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    $\begingroup$ Every time anyone counts something, they're tacitly claiming a bijection. If your question is not about who was the first human to count, then you have to make it more precise and explain what examples do count (i.e. don't just count). $\endgroup$ Commented Sep 10, 2023 at 2:39
  • $\begingroup$ I heard that in Pirahã language there is no words for counting, but there are names for children. So bijection may actually predate counting, as the latter is more about the order and not only one-to-one correspondence, and in this case my question becomes hopeless. $\endgroup$
    – kerzol
    Commented Sep 10, 2023 at 12:04


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