From: Dana Scott <scott@cs.cmu.edu>
To: categories@mta.ca
Subject: An elementary question
Date: Sun, 13 Aug 2017 12:55:11 -0700 [thread overview]
Message-ID: <E1dh2U9-0000c9-3y@mlist.mta.ca> (raw)
The category of posets (= partially ordered sets) and monotone
maps is often used as an easy example -- different from the category
of sets -- that has products, coproducts, and is cartesian closed
but not a topos.
Let P and Q be two posets. Define (P (<) Q) as the modified
coproduct where all the elements of P are made less than all the
elements of Q. QUESTION. Does (P (<) Q) have a nice categorical
definition as a functor in the category of posets?
[For admin and other information see: http://www.mta.ca/~cat-dist/ ]
next reply other threads:[~2017-08-13 19:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-13 19:55 Dana Scott [this message]
2017-08-14 0:15 ` alex
2017-08-14 4:42 ` Patrik Eklund
2017-08-14 18:43 ` Mike Stay
2017-08-15 5:57 ` Vaughan Pratt
[not found] ` <fa2a57444ecc56bfc61165f2263d42e5@cs.umu.se>
2017-08-15 14:21 ` Mike Stay
2017-08-14 8:00 ` Paul Blain Levy
2017-08-14 18:51 ` Robin Cockett
[not found] ` <CAKQgqTb4f=+Y=SuCu26AKg3Wd02friY_6z9FhukXiSnoapLZRQ@mail.gmail.com>
2017-08-15 4:50 ` Patrik Eklund
2017-08-15 21:49 ` Joachim Kock
2017-08-17 2:02 ` Branko Nikolić
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=E1dh2U9-0000c9-3y@mlist.mta.ca \
--to=scott@cs.cmu.edu \
--cc=categories@mta.ca \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).