Robert Bartnik
Robert Bartnik is an Australian mathematician based at Monash University, where he holds the position of Professor of Pure Mathematics.  He is known for his contribution to general relativity, particularly for demonstrating that the ADM mass of an asymptotically flat spacetime is a well-defined quantity.  He gained his bachelor's and master's degrees from Melbourne University and his PhD from Princeton University in 1983.  His dissertation subject was "Existence of Maximal Hypersurfaces".  His doctoral advisor was Shing-Tung Yau. In 2004 he was elected as a fellow of the Australian Academy of Science at which time it was noted He is perhaps best known for his work with John McKinnon on particle-like solutions of the Einstein Yang–Mills equation, but he has worked widely on applications of geometry and analysis to the study of spacetime structure. 

He was a visiting scholar at the Institute for Advanced Study in 1980-81.