categories - Category Theory list
 help / color / mirror / Atom feed
From: John Baez <baez@math.ucr.edu>
To: categories <categories@mta.ca>
Subject: Re: cartesian closed categories and holodeck games
Date: Mon, 23 Oct 2006 23:24:23 -0700	[thread overview]
Message-ID: <E1GcLMO-00026c-QL@mailserv.mta.ca> (raw)

On Mon, Oct 23, 2006 at 11:15:04PM -0700, Vaughan Pratt wrote:

> In your Week 240 post to categories, you said
>
> > The moral of this game is that all systematic methods for picking
> > an element of (X^X)^(X^X) for an unknown set X can be written
> > using the lambda calculus.

> What is unsystematic about the contagious-fixpoint functional?  This is the
> functional that maps those functions that have any fixpoints to the identity
> function (the function that makes every element a fixpoint) and functions
> without fixpoints to themselves (thus preserving the absence of fixpoints).

Whoops.  I got carried away there.  Later I admitted that by "systematic
method" I just meant "definable using the lambda calculus".  I'll have to
fix this.  Thanks!

Best,
jb





             reply	other threads:[~2006-10-24  6:24 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-10-24  6:24 John Baez [this message]
  -- strict thread matches above, loose matches on Subject: below --
2006-10-24  6:15 Vaughan Pratt
2006-10-23 20:59 John Baez
2006-10-23 17:39 Dominic Hughes
2006-10-23  1:26 John Baez

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=E1GcLMO-00026c-QL@mailserv.mta.ca \
    --to=baez@math.ucr.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).