categories - Category Theory list
 help / color / mirror / Atom feed
From: William Messing <messing@math.umn.edu>
To: "Eduardo J. Dubuc" <edubuc@dm.uba.ar>
Cc: Categories list <categories@mta.ca>
Subject: Re: size_question_reloaded
Date: Mon, 04 Jul 2011 08:11:04 -0500	[thread overview]
Message-ID: <E1QeUpu-0005Or-9v@mlist.mta.ca> (raw)
In-Reply-To: <E1QdgvK-0008S4-4x@mlist.mta.ca>

Concerning Eduardo's question: Now, if you work with a  Grothendieck 
base topos “as if it were the category of sets”, you are forced to 
specify which small category of finite sets you are using,    or not ?.

No, in the definition of an U-topos, E,  given in SGA 4, Expose IV, § 1, 
it is required that E has an U-small (topologically) generating set of 
objects.  Bu such a set  or, equivalently, full subcategory of E, is not 
part of the data.

Bill Messing


[For admin and other information see: http://www.mta.ca/~cat-dist/ ]


  reply	other threads:[~2011-07-04 13:11 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-07-03 22:59 size_question_reloaded Eduardo J. Dubuc
2011-07-04 13:11 ` William Messing [this message]
2011-07-05  9:37 ` size_question_reloaded Steven Vickers

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=E1QeUpu-0005Or-9v@mlist.mta.ca \
    --to=messing@math.umn.edu \
    --cc=categories@mta.ca \
    --cc=edubuc@dm.uba.ar \
    /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).