This web presentation contains the
audio and slides
of a lecture given at the Fields Institute on October 1, 2002
as part of the Graduate Course on Descriptive Set Theory.
MP3 format
(downloadable too; right-click to download)
You may browse the slides
in the presentation (a browser capable of displaying PNG graphics
is required).
Or, you may download a higher-resolution printer-ready
version
in PDF format
(requires Acrobat Reader).