69 citations · 72 across the 3 of their papers we have counts for
3 papers
math.FA2014★ 1 cited
Maps on real Hilbert spaces preserving the area of parallelograms and a preserver problem on self-adjoint operators
György Pál Gehér
In this paper first we describe all (not necessarily linear or bijective) transformations on with which preserve the area of parallelograms spanned…
math.FA2014★ 2 cited
Maps on classes of Hilbert space operators preserving measure of commutativity
György Pál Gehér, Gergő Nagy
In this paper first we give a partial answer to a question of L. Molnár and W. Timmermann. Namely, we will describe those linear (not necessarily bijective) transformations on the…
math-ph2014★ 69 cited
An elementary proof for the non-bijective version of Wigner's theorem
Gy. P. Gehér
The non-bijective version of Wigner's theorem states that a map which is defined on the set of self-adjoint, rank-one projections (or pure states) of a complex Hilbert space and wh…