{"paper":{"title":"Backbone colouring of chordal graphs","license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","headline":"","cross_cats":["cs.DM"],"primary_cat":"math.CO","authors_text":"J\\'ulio Ara\\'ujo, Lucas Picasarri-Arrieta, Nicolas Nisse","submitted_at":"2025-08-05T01:11:58Z","abstract_excerpt":"A proper $k$-colouring of a graph $G=(V,E)$ is a function $c: V(G)\\to \\{1,\\ldots,k\\}$ such that $c(u)\\neq c(v)$ for every edge $uv\\in E(G)$. The chromatic number $\\chi(G)$ is the minimum $k$ such that there exists a proper $k$-colouring of $G$. Given a spanning subgraph $H$ of $G$, a $q$-backbone $k$-colouring of $(G,H)$ is a proper $k$-colouring $c$ of $G$ such that $\\lvert c(u)-c(v)\\rvert \\ge q$ for every edge $uv\\in E(H)$. The $q$-backbone chromatic number ${\\rm BBC}_q(G,H)$ is the smallest $k$ for which there exists a $q$-backbone $k$-colouring of $(G,H)$. In their seminal paper, Broersma "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2508.02980","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2508.02980/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}