CAUTION: The Sender of this email is not from within Dalhousie. Hi Uwe, 1. No. It was introduced in: P. Freyd. "Properties Invariant within Equivalence Types of Categories". In: Algebra, Topology and Category Theory: A Collection of Papers in Honour of Samuel Eilenberg. Ed. by A. Heller and M. Tierney. Academic Press, 1976, pp. 55-61. 2. I am interested in the answer of this question too... can you share your answers with the list? I use Freyd's language a lot, with the modifications described here: http://angg.twu.net/math-b.html#favorite-conventions https://arxiv.org/abs/2006.15836 Cheers =), Eduardo Ochs http://angg.twu.net/math-b.html http://angg.twu.net/dednat6.html On Fri, 11 Dec 2020 at 23:20, Uwe Egbert Wolter <Uwe.Wolter@uib.no> wrote:
Dear all,
only some weeks ago I became aware of "the language of diagrams" introduced in "Categories, allegories" by Freyd/Scedrov.
Two questions: 1. Is this the first place where this language has been described and defined? 2. Has this language been further elaborated and/or applied at other places?
Best regards
Uwe
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