3 papers
math.CO2025
Graph covers and semi-covers: Who is stronger?
Jan Kratochvil, Roman Nedela
The notion of graph cover, also known as locally bijective homomorphism, is a discretization of covering spaces known from general topology. It is a pair of incidence-preserving ve…
math.CO2025
Berge's conjecture for cubic graphs with small colouring defect
Ján Karabáš, Edita MáÄajová, Roman Nedela +1
A long-standing conjecture of Berge suggests that every bridgeless cubic graph can be expressed as a union of at most five perfect matchings. This conjecture trivially holds for $3…
math.CO2024
The Jacobian of a graph and graph automorphisms
István Estélyi, Ján Karabáš, Alexander Mednykh +1
In the present paper we investigate the faithfulness of certain linear representations of groups of automorphisms of a graph in the group of symmetries of the Jacobian of .…