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Benjamin Dickman
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CW since some of the recent posts on MO have required little more than googling.


Prior to the book you mentioned, MacLane attributed this saying to Peter Freyd in:

MacLane, S. (1965). Categorical algebra. Bulletin of the American Mathematical Society, 71(1), 40-106.

Relevant excerpt: (p. 48)

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The only citation of Freyd in that piece (P. Freyd, Relative homological algebra made absolute, Proc. Nat. Acad. Sci. U.S.A. 49 (1963), 19-20) does not appear to be the source of this quotation (if you can call it that) so the true origin may have to remain unknown.

Benjamin Dickman
  • 7.8k
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