1. Some recent discoveries about half-arc-transitive graphs : dedicated to Dragan Marušič on the occasion of his 60th birthdayMarston D. E. Conder, Primož Potočnik, Primož Šparl, 2015, original scientific article Abstract: We present some new discoveries about graphs that are half-arc-transitive (that is, vertex- and edge-transitive but not arc-transitive). These include the recent discovery of the smallest half-arc-transitive 4-valent graph with vertex-stabiliser of order 4, and the smallest with vertex-stabiliser of order 8, two new half-arc-transitive 4-valent graphs with dihedral vertex-stabiliser ▫$D_4$▫ (of order 8), and the first known half-arc-transitive 4-valent graph with vertex-stabiliser of order 16 that is neither abelian nor dihedral. We also use half-arc-transitive group actions to provide an answer to a recent question of Delorme about 2-arc-transitive digraphs that are not isomorphic to their reverse. Keywords: graph, edge-transitive, vertex-transitive, arc-transitive, half arc-transitive Published in RUP: 31.12.2021; Views: 827; Downloads: 16 Full text (333,06 KB) |
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3. Edge elimination and weighted graph classesJesse Beisegel, Nina Chiarelli, Ekkehard Köhler, Matjaž Krnc, Martin Milanič, Nevena Pivač, Robert Scheffler, Martin Strehler, 2020, published scientific conference contribution Keywords: edge elimination, weighted graph, split graph, threshold graph, chain graph, linear-time recognition algorithm Published in RUP: 10.11.2020; Views: 1384; Downloads: 34 Link to full text |
4. Edge elimination schemes of weighted graph classes, Workshop on Graph Modification algorithms, experiments and new problems, 23rd - 24th January 2020, Bergen, NorwayMartin Milanič, Jesse Beisegel, Nina Chiarelli, Ekkehard Köhler, Matjaž Krnc, Nevena Pivač, Robert Scheffler, Martin Strehler, 2020, unpublished invited conference lecture Keywords: graph class, edge elimination scheme, sandwich monotonicity Published in RUP: 28.05.2020; Views: 1418; Downloads: 0 |
5. Avoidable vertices and edges in graphsJesse Beisegel, Maria Chudnovsky, Vladimir Gurvich, Martin Milanič, Mary Agnes Milanič, 2019, published scientific conference contribution Keywords: simplicial vertex, avoidable vertex, avoidable edge, avoidable path, maximum weight clique problem, polynomial-time algorithm, hole-cyclically orientable graph Published in RUP: 20.08.2019; Views: 2015; Downloads: 156 Link to full text |
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9. On two extensions of equimatchable graphsZakir Deniz, Tinaz Ekim, Tatiana Romina Hartinger, Martin Milanič, Mordechai Shalom, 2017, original scientific article Keywords: minimum maximal matching, equimatchable graph, edge dominating set, Gallai-Edmonds decomposition, parameterized complexity Published in RUP: 29.01.2018; Views: 2228; Downloads: 146 Link to full text |
10. On cyclic edge-connectivity of fullerenesKlavdija Kutnar, Dragan Marušič, 2008, original scientific article Abstract: A graph is said to be cyclically ▫$k$▫-edge-connected, if at least ▫$k$▫ edges must be removed to disconnect it into two components, each containing a cycle. Such a set of ▫$k$▫ edges is called a cyclic-k-edge cutset and it is called a trivial cyclic-k-edge cutset if at least one of the resulting two components induces a single ▫$k$▫-cycle. It is known that fullerenes, that is, 3-connected cubic planar graphs all of whose faces are pentagons and hexagons, are cyclically 5-edge-connected. In this article it is shown that a fullerene ▫$F$▫ containing a nontrivial cyclic-5-edge cutset admits two antipodal pentacaps, that is, two antipodal pentagonal faces whose neighboring faces are also pentagonal. Moreover, it is shown that ▫$F$▫ has a Hamilton cycle, and as a consequence at least ▫$15 \cdot 2^{n/20-1/2}$▫ perfect matchings, where ▫$n$▫ is the order of ▫$F$▫. Keywords: graph, fullerene graph, cyclic edge-connectivity, hamilton cycle, perfect matching Published in RUP: 03.04.2017; Views: 2126; Downloads: 138 Link to full text |