Seminar of Graph Theory - Jozef Širáň (12.12.2024)
Thursday 12.12.2024 at 9:50, Lecture room M 213
Jozef Širáň (Slovak University of Technology, Bratislava):
Orientably-regular embeddings of multigraphs
Abstract:
Informally, a graph embedding on some orientable surface gives an orientably-regular map if the embedding exhibits the `highest level of orientation-preserving symmetry'. Inspection of Conder's list of orientably-regular maps up to genus 300 reveals that nearly 90 per cent of them are such that either the map or its dual has a non-simple underlying graph, generating thus legitimate interest in orientably-regular embeddings of multigraphs. In the talk we will explain an approach to this topic based on group presentations and apply it to classification of regular embeddings of complete multigraphs.