Heinz Langer achieved significant, deep results in a wide range of mathematics,
including spectral theory of operators in Krein spaces, selfadjoint operator polynomials,
extension theory of symmetric operators, and block operator matrices.
Since 1973, he has contributed seven definitive research papers
to Acta Scientiarum Mathematicarum,
two of them jointly with M.G. Krein.
In particular,
they introduced the notion of generalized Nevanlinna functions, widely used today,
and exploited the method of B. Sz.Nagy and A. Korányi
to relate analytic functions and linear operators.
The Medal was presented to Heinz Langer at 14:00, December 16, 2009
in the Bolyai Institute.
On this occasion he delivered a lecture ``Selfadjoint analytic operator functions: Local spectral function and inner linearization".
