Category-theory interactive demonstrations on the Web

[Jocelyn Ireson-Paine <popx@j-paine.org>]

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/ ]