{ "id": "2102.02010", "version": "v1", "published": "2021-02-03T11:25:00.000Z", "updated": "2021-02-03T11:25:00.000Z", "title": "Inducibility and universality for trees", "authors": [ "Timothy F. N. Chan", "Daniel Kral", "Bojan Mohar", "David R. Wood" ], "comment": "31 pages, 8 figures", "categories": [ "math.CO" ], "abstract": "We answer three questions posed by Bubeck and Linial on the limit densities of subtrees in trees. We prove there exist positive $\\varepsilon_1$ and $\\varepsilon_2$ such that every tree that is neither a path nor a star has inducibility at most $1-\\varepsilon_1$, where the inducibility of a tree $T$ is defined as the maximum limit density of $T$, and that there are infinitely many trees with inducibility at least $\\varepsilon_2$. Finally, we construct a universal sequence of trees; that is, a sequence in which the limit density of any tree is positive.", "revisions": [ { "version": "v1", "updated": "2021-02-03T11:25:00.000Z" } ], "analyses": { "keywords": [ "inducibility", "universality", "maximum limit density", "universal sequence" ], "note": { "typesetting": "TeX", "pages": 31, "language": "en", "license": "arXiv", "status": "editable" } } }