activity
20232025
collaborators

6 papers

math.CO2025

Hardness of Planarity for Weak Temporal Sequences of 2-Connected Graphs

Johannes Carmesin, Will J. Turner

A weak deletion sequence is a sequence of graphs so that for each either is isomorphic to a subgraph of , or vice versa: is…

cs.SI2025

How Local Separators Shape Community Structure in Large Networks

Sarah Frenkel, Johannes Carmesin

Community detection is a key tool for analyzing the structure of large networks. Standard methods, such as modularity optimization, focus on identifying densely connected groups bu…

math.CO2025

A Graph Minors Approach to Temporal Sequences

Johannes Carmesin, Will J. Turner

We develop a structural approach to simultaneous embeddability in temporal sequences of graphs, inspired by graph minor theory. Our main result is a classification theorem for 2-co…

math.CO2024

Towards a Stallings-type theorem for finite groups

Johannes Carmesin, George Kontogeorgiou, Jan Kurkofka +1

A recent development in graph-minor theory is to study local separators, vertex-sets that separate graphs locally but not necessarily globally. The local separators of a graph roug…

cs.DM2023

How to apply tree decomposition ideas in large networks?

Johannes Carmesin, Sarah Frenkel

Graph decompositions are the natural generalisation of tree decompositions where the decomposition tree is replaced by a genuine graph. Recently they found theoretical applications…

math.CO2023

Characterising 4-tangles through a connectivity property

Johannes Carmesin, Jan Kurkofka

Every large -connected graph-minor induces a -tangle in its ambient graph. The converse holds for , but fails for . This raises the question whether `-conn…