Janos Kannar died on January 13, 2024, in the 56th year of his life. He is survived by his mother, his wife and his daughters Eszter and Katalin.
Janos completed his doctoral studies at the Theoretical Department of RMKI and received his Ph.D. in 1995 with his thesis “Investigations of Spacetime Singularities in General Relativity and Einstein-Cartan Theory”. He then completed his postdoctoral training in the relativity group at the Max Planck Institute for Physics and Astrophysics in Munich and as a postdoctoral fellow in the mathematical relativity research group at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute) in Potsdam. Janos is best known for determining, in collaboration with Helmut Friedrich, the behavior of various fields characterizing Bondi systems in the region of spacetime where null infinity touches spacelike infinity. They related these fields, in particular the Newmann-Penrose constants, to the behavior of the initial data near spacelike infinity.
After returning to Hungary, Janos became a Senior Research Fellow at the Theoretical Department of RMKI, where his research continued to be related to important problems in mathematical relativity, such as singularity theorems or the Cauchy problem. During the last two decades, Janos’s talents have left traces in the development of new technologies of international companies such as Nokia, SAP and GE.
His outstanding skills were matched by a modest, always helpful, but incredibly focused character.
Helmut Friedrich and Istvan Racz