From: selinger@mathstat.dal.ca (Peter Selinger)
To: categories@mta.ca (Categories List)
Subject: Re: opposite category
Date: Thu, 14 Sep 2017 12:58:34 -0300 (ADT) [thread overview]
Message-ID: <E1dsucr-0002B6-7j@mlist.mta.ca> (raw)
In-Reply-To: <E1dpdrs-000362-Vy@mlist.mta.ca>
Robert Pare wrote:
>
> He said there may come a time when we have to consider covariant
> functors as contravariant ones on the opposite category.
This anecdote seems to have prompted a few posts about opposite
categories, but I thought the point of the original anecdote was that
Fred said that *covariant* functors should be considered as
contravariant functors on the opposite category, i.e., that he
considered contravariant functors to be the more fundamental concept.
An interesting thought, and obviously tongue-in-cheek.
-- Peter
[For admin and other information see: http://www.mta.ca/~cat-dist/ ]
next prev parent reply other threads:[~2017-09-14 15:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1EE29452-3443-447D-BCDE-0A76B4F0562D@dal.ca>
2017-09-06 16:51 ` Fred Robert Pare
2017-09-07 0:42 ` Fred Ross Street
2017-09-14 15:58 ` Peter Selinger [this message]
2017-09-15 18:23 ` opposite category Joachim Kock
2017-09-16 1:20 ` Vaughan Pratt
2017-09-16 15:44 ` Joyal, André
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