4 papers
Automorphisms of graphs corresponding to conjugacy classes of finite-rank self-adjoint operators
Mark Pankov, Krzysztof Petelczyc, Mariusz Zynel
We consider the graph whose vertex set is a conjugacy class consisting of finite-rank self-adjoint operators on a complex Hilbert space . The dimension of is…
Automorphisms and some geodesic properties of ortho-Grassmann graphs
Mark Pankov, Krzysztof Petelczyc, Mariusz Zynel
Let be a complex Hilbert space. Consider the ortho-Grassmann graph whose vertices are -dimensional subspaces of (projections of rank ) and two subs…
Generalized Grassmann graphs associated to conjugacy classes of finite-rank self-adjoint operators
Mark Pankov, Krzysztof Petelczyc, Mariusz Zynel
Two distinct projections of finite rank are adjacent if their difference is an operator of rank two or, equivalently, the intersection of their images is -dimensional. W…
The complement of a subspace in a classical polar space
Krzysztof Petelczyc, Mariusz Żynel
In a polar space, embeddable into a projective space, we fix a subspace, that is contained in some hyperplane. The complement of that subspace resembles a slit space or a semiaffin…