Zobrazeno 1 - 10
of 121
pro vyhledávání: '"Hamann, Matthias"'
Autor:
Abrishami, Tara, Esperet, Louis, Giocanti, Ugo, Hamann, Matthias, Knappe, Paul, Möller, Rögnvaldur G.
We study the existence of periodic colorings and orientations in locally finite graphs. A coloring or orientation of a graph $G$ is periodic if the resulting colored or oriented graph is quasi-transitive, meaning that $V(G)$ has finitely many orbits
Externí odkaz:
http://arxiv.org/abs/2411.01951
Autor:
Hamann, Matthias
We prove that every locally finite quasi-transitive graph that does not contain $K_\infty$ as a minor is quasi-isometric to some planar quasi-transitive locally finite graph. This solves a problem of Esperet and Giocanti and improves their recent res
Externí odkaz:
http://arxiv.org/abs/2405.17218
Autor:
Hamann, Matthias
In this paper, we prove that infinite cancellative finitely generated hyperbolic monoids never contain $\mathbb N\times\mathbb N$ as a submonoid but that they contain an element of infinite order and, if they are elementary, then they also contain a
Externí odkaz:
http://arxiv.org/abs/2403.07374
Autor:
Hamann, Matthias
Based on a notion by Gray and Kambites of hyperbolicity in the setting of semimetric spaces like digraphs or semigroups, we will construct (under a small additional geometric assumption) a boundary based on quasi-geodesic rays and anti-rays that is p
Externí odkaz:
http://arxiv.org/abs/2403.06127
Halin's well-known grid theorem states that a graph $G$ with a thick end must contain a subdivision of the hexagonal half-grid. We obtain the following strengthening when $G$ is vertex-transitive and locally finite. Either $G$ is quasi-isometric to a
Externí odkaz:
http://arxiv.org/abs/2403.05862
Autor:
Hamann, Matthias
In this note, we show that locally finite quasi-transitive graphs are quasi-isometric to trees if and only if every other locally finite quasi-transitive graph quasi-isometric to them is minor excluded. This generalizes results by Ostrovskii and Rose
Externí odkaz:
http://arxiv.org/abs/2110.12841
Autor:
Hamann, Matthias
Gray and Kambites introduced a notion of hyperbolicity in the setting of semimetric spaces like digraphs or semigroups. We will prove that under a small additional geometric assumption their notion of hyperbolicity is preserved by quasi-isometries. A
Externí odkaz:
http://arxiv.org/abs/2110.13049
We generalise the standard constructions of a Cayley graph in terms of a group presentation by allowing some vertices to obey different relators than others. The resulting notion of presentation allows us to represent every vertex transitive graph. A
Externí odkaz:
http://arxiv.org/abs/2007.06432
Autor:
Hamann, Matthias, Miraftab, Babak
We prove two characterisations of accessibility of locally finite quasi-transitive connected graphs. First, we prove that any such graph $G$ is accessible if and only if its set of separations of finite order is an ${\rm Aut}(G)$-finitely generated s
Externí odkaz:
http://arxiv.org/abs/2003.14203
We prove that every graph has a canonical tree of tree-decompositions that distinguishes all principal tangles (these include the ends and various kinds of large finite dense structures) efficiently. Here `trees of tree-decompositions' are a slightly
Externí odkaz:
http://arxiv.org/abs/2002.12030