From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/8387 Path: news.gmane.org!not-for-mail From: Jocelyn Ireson-Paine Newsgroups: gmane.science.mathematics.categories Subject: Category-theory interactive demonstrations on the Web Date: Fri, 14 Nov 2014 16:24:59 +0000 (GMT) Message-ID: Reply-To: Jocelyn Ireson-Paine NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII X-Trace: ger.gmane.org 1415997134 22144 80.91.229.3 (14 Nov 2014 20:32:14 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 14 Nov 2014 20:32:14 +0000 (UTC) To: categories@mta.ca Original-X-From: majordomo@mlist.mta.ca Fri Nov 14 21:32:09 2014 Return-path: Envelope-to: gsmc-categories@m.gmane.org Original-Received: from smtp3.mta.ca ([138.73.1.127]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XpNXM-0000zM-2H for gsmc-categories@m.gmane.org; Fri, 14 Nov 2014 21:32:08 +0100 Original-Received: from mlist.mta.ca ([138.73.1.63]:60956) by smtp3.mta.ca with esmtp (Exim 4.80) (envelope-from ) id 1XpNWi-0002hg-7m; Fri, 14 Nov 2014 16:31:28 -0400 Original-Received: from majordomo by mlist.mta.ca with local (Exim 4.71) (envelope-from ) id 1XpNWh-0007LR-UP for categories-list@mlist.mta.ca; Fri, 14 Nov 2014 16:31:27 -0400 Precedence: bulk Xref: news.gmane.org gmane.science.mathematics.categories:8387 Archived-At: Dear readers, here's something I'm pleased with, which I like to advertise every so often. It's a program running on my Web server which demonstrates category theory by calculating constructs in the category of sets: http://www.j-paine.org/cgi-bin/webcats/webcats.php . The page contains instructions, followed by a form which lets you ask the server to calculate products, equalisers, etc. For example, you can ask it to calculate the product of sets A and B. You either type in values for the sets, or let it choose them, and it will calculate the product object and projection arrows. It will then send back the page, but headed with a link to your results. These contain a diagram, values for all its objects and arrows, and an explanation. And, just to make the diagram more vivid, it rendered in VRML so that you can pick it up and move it about. To show how general category theory is, I used the same code to calculate the limit and colimit of simple diagrams representing systems of interacting objects. You can see a demo of that at http://www.j-paine.org/slp_demo.html . Cheers, Jocelyn Ireson-Paine 07768 534 091 http://www.jocelyns-cartoons.uk http://www.j-paine.org [For admin and other information see: http://www.mta.ca/~cat-dist/ ]