A well-known result of Brylawski constructs an elementary lift of a matroid M from a linear class of circuits of M. We generalize this result by constructing a rank-k lift of M from a rank-k matroid on the set of circuits of M. We conjecture that every lift of M arises via this construction. We then apply this result to group-labeled graphs, generalizing a construction of Zaslavsky. Given a graph G with edges labeled by a group, Zaslavsky's lift matroid K is an elementary lift of the graphic matroid M(G) that respects the group-labeling; specifically, the cycles of G that are circuits of K coincide with the cycles that are balanced with respect to the group-labeling. For k 2, when does there exist a rank-k lift of M(G) that respects the group-labeling in this same sense? For abelian groups, we show that such a matroid exists if and only if the group is isomorphic to the additive group of a non-prime finite field.
Publication Source (Journal or Book title)
ELECTRONIC JOURNAL OF COMBINATORICS
Walsh, Z. (2022). A new matroid lift construction and an application to group-labeled graphs. ELECTRONIC JOURNAL OF COMBINATORICS, 29 (1) https://doi.org/10.37236/10372