categories - Category Theory list
 help / color / mirror / Atom feed
From: "Martín Hötzel Escardó" <m.escardo@cs.bham.ac.uk>
To: categories <categories@mta.ca>
Subject: Terminology regarding injectivity of objects
Date: Fri, 8 Feb 2019 19:47:34 +0000	[thread overview]
Message-ID: <E1gsTSw-0001qm-E9@mlist.mta.ca> (raw)


(1) An object D is called injective over an arrow j:X->Y if the
"restriction map"

      hom(Y,D) -> hom(X,D)
          g   |-> g o j

is a surjection. This is fairly standard terminology (where does it come
from, by the way).

(2) I am working with the situation where the restriction map is a
*split* surjection.

I though of the terminology "D is split injective over j", but perhaps
this is awkward. Is there a standard terminology for this notion. Or,
failing that, a terminology that at least one person has already used in
the literature or in the folklore. Or, failing that too, a good
suggestion by any of you?

Thanks,
Martin


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


             reply	other threads:[~2019-02-08 19:47 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-08 19:47 Martín Hötzel Escardó [this message]
     [not found] ` <Prayer.1.3.5.1902092143340.28331@prayer.maths.cam.ac.uk>
2019-02-09 23:43   ` Martin Escardo
2019-02-22 23:02   ` Martin Escardo

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=E1gsTSw-0001qm-E9@mlist.mta.ca \
    --to=m.escardo@cs.bham.ac.uk \
    --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).