Published Paper
Inserted: 10 aug 2022
Last Updated: 7 oct 2024
Journal: Homology, Homotopy and Applications
Volume: 26
Number: 2
Pages: 137 – 161
Year: 2022
Doi: 10.4310/HHA.2024.v26.n2.a7
Abstract:
In this paper, we extend the definition of cohomology associated to monotone graph properties, to encompass twisted functor coefficients. We introduce oriented matchings on graphs, and focus on their (twisted) cohomology groups. We characterise oriented matchings in terms of induced free-flow pseudoforests, and explicitly determine the homotopy type of the associated simplicial complexes. Furthermore, we provide a connection between the cohomology of oriented matchings with certain functor coefficients, and the recently defined multipath cohomology. Finally, we define a further oriented homology for graphs and interpret it as a count of free-flow orientations.