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From: Eduardo Ochs <eduardoochs@gmail.com>
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Subject: Re: The language of diagrams
Date: Sat, 12 Dec 2020 02:38:34 -0300
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To: Uwe Egbert Wolter <Uwe.Wolter@uib.no>
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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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