Metric rigidity of crystallographic groups.
Microlocal Approach to Tensor Tomography and Boundary and Lens Rigidity
2000 Mathematics Subject Classification: 53C24, 53C65, 53C21.This is a survey of the recent results by the author and Gunther Uhlmann on the boundary rigidity problem and on the associated tensor tomography problem.Author partly supported by NSF Grant DMS-0400869.
Minimal surfaces, the Dirac operator and the Penrose inequality