Chow's theorem for Hilbert Grassmannians as a Wigner-type theorem
Abstract
Let be an infinite-dimensional complex Hilbert space. Denote by the Grassmannian formed by closed subspaces of whose dimension and codimension both are infinite. We say that are {\it ortho-adjacent} if they are compatible and is a hyperplane in both . A subset is called an -{\it component} if for any the intersection is of the same finite codimension in both and is maximal with respect to this property. Let be a bijective transformation of preserving the ortho-adjacency relation in both directions. We show that the restriction of to every -component of is induced by a unitary or anti-unitary operator or it is the composition of the orthocomplementary map and a map induced by a unitary or anti-unitary operator. Note that the restrictions of to distinct components can be related to different operators.
Cite
@article{arxiv.2302.01077,
title = {Chow's theorem for Hilbert Grassmannians as a Wigner-type theorem},
author = {Mark Pankov and Adam Tyc},
journal= {arXiv preprint arXiv:2302.01077},
year = {2023}
}