categories - Category Theory list
 help / color / mirror / Atom feed
From: RJ Wood <rjwood@mathstat.dal.ca>
To: categories@mta.ca
Cc: Rj Wood <rjwood@mathstat.dal.ca>
Subject: Re: Where does the term monad come from?
Date: Mon, 6 Apr 2009 23:06:37 -0300 (ADT)	[thread overview]
Message-ID: <E1Lr9Ol-0001OC-46@mailserv.mta.ca> (raw)

John Baez wrote:

It's pretty much been said, but I'll say it again:

We can generalize the concept of monoid from Set to any monoidal category
and then to any bicategory.  A monoid in Cat is then a monad.

Indeed, most people seem to call a "monoid" in a bicategory a "monad".

Best,
jb

John, given the didactic nature of this thread, I think we should be
more precise about what you mean by `a "monoid" in a bicategory'. For
a bicategory B and an object X therein, B(X,X) (together with composition,
1_X, and the inherited constraints of B)  i s  a monoidal category and a
monad in B is an object X in B together with a monoid in B(X,X).
Rj




             reply	other threads:[~2009-04-07  2:06 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-04-07  2:06 RJ Wood [this message]
  -- strict thread matches above, loose matches on Subject: below --
2009-04-12  1:30 Steve Lack
2009-04-11 15:43 Thorsten Altenkirch
2009-04-07 16:50 Zinovy Diskin
2009-04-07 15:10 jim stasheff
2009-04-07  7:32 Vaughan Pratt
2009-04-06 20:24 John Baez
2009-04-06  4:52 Patrik Eklund
2009-04-03 13:55 burroni
2009-04-03  4:33 Steve Lack
2009-04-03  4:28 Steve Lack
2009-04-02 13:31 jim stasheff
2009-04-01 21:19 burroni
2009-04-01 19:47 Venanzio Capretta
2009-04-01 18:45 Johannes.Huebschmann
2009-04-01 18:13 Michael Barr
2009-04-01 11:24 Thorsten Altenkirch

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=E1Lr9Ol-0001OC-46@mailserv.mta.ca \
    --to=rjwood@mathstat.dal.ca \
    --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).