Space-time presents itself in string theory in the exotic form of a conformal quantum field theory. I shall describe the mathematical structures involved, how they relate to ordinary geometry, and how they play a role in other mathematical contexts, especially the representation theory of loop groups. The first lecture will set up the framework, and will then turn to loop groups. The second and third lectures will be concerned with space-time in string theory.

Article on Lecture

Some links to his work: http://www.cgtp.duke.edu/ITP99/segal/