{ "id": "2111.00532", "version": "v2", "published": "2021-10-31T16:16:28.000Z", "updated": "2024-02-06T14:06:22.000Z", "title": "Pure pairs. IX. Transversal trees", "authors": [ "Alex Scott", "Paul Seymour", "Sophie Spirkl" ], "comment": "Accepted manuscript; see DOI for journal version", "journal": "SIAM Journal on Discrete Mathematics, Volume 38(1), 2024, pp. 645-667", "doi": "10.1137/21M1456509", "categories": [ "math.CO" ], "abstract": "Fix k>0, and let G be a graph, with vertex set partitioned into k subsets (`blocks') of approximately equal size. An induced subgraph of G is transversal (with respect to this partition) if it has exactly one vertex in each block (and therefore it has exactly k vertices). A pure pair in G is a pair X,Y of disjoint subsets of V(G) such that either all edges between X,Y are present or none are; and in the present context we are interested in pure pairs (X,Y) where each of X,Y is a subset of one of the blocks, and not the same block. This paper collects several results and open questions concerning how large a pure pair must be present if various types of transversal subgraphs are excluded.", "revisions": [ { "version": "v2", "updated": "2024-02-06T14:06:22.000Z" } ], "analyses": { "keywords": [ "pure pair", "transversal trees", "disjoint subsets", "transversal subgraphs", "vertex set" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }