Speaker
Carolyn Chun
(University of Maryland)
Description
By ``cutting out'' the edges and vertices of a graph cellularly embedded in a surface, we obtain a ribbon graph. A partial Petrial is obtained from a ribbon graph by selecting a subset of the ribbon edges adding a half-twist to each. Delta-matroids generalize ribbon graphs similarly to the way that matroids generalize graphs. The ribbon graph partial Petrial is the analogue of a more general delta-matroid operation. In this talk, we characterize the set of delta-matroids that is closed under this delta-matroid operation by a set of minimal obstructions.
Primary author
Carolyn Chun
(University of Maryland)
Co-authors
Prof.
Iain Moffatt
(Royal Holloway University of London)
Dr
Ralf Rueckriemen
(Royal Holloway University of London)
Prof.
Steven Noble
(Birkbeck, University of London)
