Chordal signed graphs and signed bigraphs
Abstract
Chordal graphs and chordal bigraphs enjoy beautiful characterizations, in terms of forbidden subgraphs, vertex/edge orderings, vertex/edge separating sets, and tree-like representations. In this paper, we introduce chordal signed graphs and chordal signed bigraphs. Interestingly, chordal signed graphs are equivalent to strict chordal digraphs studied by Hell and Hern\'andez-Cruz. A forbidden subdigraph characterization of strict chordal digraphs can be translated to a forbidden subgraph characterization of chordal signed graphs. We give a forbidden subgraph characterization of chordal signed bigraphs. The forbidden subgraphs for chordal signed bigraphs are analogous to those for chordal signed graphs but the proofs are much more complicated and intriguing.
Keywords
Cite
@article{arxiv.2512.14886,
title = {Chordal signed graphs and signed bigraphs},
author = {Jing Huang and Ying Ying Ye},
journal= {arXiv preprint arXiv:2512.14886},
year = {2026}
}
Comments
28 pages, 13 figures