On elliptic genera and theta-functions
The author gives a unified new proof of the Witten rigidity theorem for some elliptic operators commuting with a circle action. He makes essential use of a new feature of loop spaces and loop groups, the modular invariance. Actually he shows that modular invariance implies rigidity. Some new properties of elliptic genera and their relationships with theta functions are also discussed.
scientific article; zbMATH DE number 912192