Evangelos Protopapas

collaborators

3 papers

math.CO2024

Generating strongly 2-connected digraphs

Meike Hatzel, Stephan Kreutzer, Evangelos Protopapas +3

We prove that there exist four operations such that given any two strongly $2$ -connected digraphs $H$ and $D$ where $H$ is a butterfly-minor of $D$ , there exists a sequence $D_0,\d…

math.CO2024

Obstructions to Erdős-Pósa Dualities for Minors

Christophe Paul, Evangelos Protopapas, Dimitrios M. Thilikos +1

Let $G$ and $H$ be minor-closed graph classes. The pair $(H, G)$ is an Erdős-Pósa pair (EP-pair) if there is a function $f$ where, for every $k$ and ever…

math.CO2024

Delineating Half-Integrality of the Erdős-Pósa Property for Minors: the Case of Surfaces

Christophe Paul, Evangelos Protopapas, Dimitrios M. Thilikos +1

In 1986 Robertson and Seymour proved a generalization of the seminal result of Erdős and Pósa on the duality of packing and covering cycles: A graph has the Erdős-Pósa property for…