Temat: median - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Median and quasi-median direct products of graphs
Autorzy:: Brešar, Boštjan
Jha, Pranava
Klavžar, Sandi
Zmazek, Blaž
Powiązania:: https://bibliotekanauki.pl/articles/744332.pdf
Data publikacji:: 2005
Wydawca:: Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:: median graph
direct product
quasi-median graph
isometric embeddings
convexity
Opis:: Median graphs are characterized among direct products of graphs on at least three vertices. Beside some trivial cases, it is shown that one component of G×P₃ is median if and only if G is a tree in that the distance between any two vertices of degree at least 3 is even. In addition, some partial results considering median graphs of the form G×K₂ are proved, and it is shown that the only nonbipartite quasi-median direct product is K₃×K₃.
Źródło:: Discussiones Mathematicae Graph Theory; 2005, 25, 1-2; 183-196
2083-5892
Pojawia się w:: Discussiones Mathematicae Graph Theory
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 2.

Tytuł:: Modular and median signpost systems and their underlying graphs
Autorzy:: Mulder, Henry
Nebeský, Ladislav
Powiązania:: https://bibliotekanauki.pl/articles/743171.pdf
Data publikacji:: 2003
Wydawca:: Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:: signpost system
modular graph
median graph
Opis:: The concept of a signpost system on a set is introduced. It is a ternary relation on the set satisfying three fairly natural axioms. Its underlying graph is introduced. When the underlying graph is disconnected some unexpected things may happen. The main focus are signpost systems satisfying some extra axioms. Their underlying graphs have lots of structure: the components are modular graphs or median graphs. Yet another axiom guarantees that the underlying graph is also connected. The main results of this paper concern if-and-only-if characterizations involving signpost systems satisfying additional axioms on the one hand and modular, respectively median graphs on the other hand.
Źródło:: Discussiones Mathematicae Graph Theory; 2003, 23, 2; 309-324
2083-5892
Pojawia się w:: Discussiones Mathematicae Graph Theory
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 3.

Tytuł:: Arboreal structure and regular graphs of median-like classes
Autorzy:: Brešar, Bostjan
Powiązania:: https://bibliotekanauki.pl/articles/743403.pdf
Data publikacji:: 2003
Wydawca:: Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:: median graph
tree
gatedness
amalgam
periphery
regular graph
Opis:: We consider classes of graphs that enjoy the following properties: they are closed for gated subgraphs, gated amalgamation and Cartesian products, and for any gated subgraph the inverse of the gate function maps vertices to gated subsets. We prove that any graph of such a class contains a peripheral subgraph which is a Cartesian product of two graphs: a gated subgraph of the graph and a prime graph minus a vertex. Therefore, these graphs admit a peripheral elimination procedure which is a generalization of analogous procedure in median graphs. We characterize regular graphs of these classes whenever they enjoy an additional property. As a corollary we derive that regular weakly median graphs are precisely Cartesian products in which each factor is a complete graph or a hyperoctahedron.
Źródło:: Discussiones Mathematicae Graph Theory; 2003, 23, 2; 215-225
2083-5892
Pojawia się w:: Discussiones Mathematicae Graph Theory
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 4.

Tytuł:: The periphery graph of a median graph
Autorzy:: Brešar, Boštjan
Changat, Manoj
Subhamathi, Ajitha
Tepeh, Aleksandra
Powiązania:: https://bibliotekanauki.pl/articles/744496.pdf
Data publikacji:: 2010
Wydawca:: Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:: median graph
Cartesian product
geodesic
periphery
peripheral expansion
Opis:: The periphery graph of a median graph is the intersection graph of its peripheral subgraphs. We show that every graph without a universal vertex can be realized as the periphery graph of a median graph. We characterize those median graphs whose periphery graph is the join of two graphs and show that they are precisely Cartesian products of median graphs. Path-like median graphs are introduced as the graphs whose periphery graph has independence number 2, and it is proved that there are path-like median graphs with arbitrarily large geodetic number. Peripheral expansion with respect to periphery graph is also considered, and connections with the concept of crossing graph are established.
Źródło:: Discussiones Mathematicae Graph Theory; 2010, 30, 1; 17-32
2083-5892
Pojawia się w:: Discussiones Mathematicae Graph Theory
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 5.

Tytuł:: On θ-graphs of partial cubes
Autorzy:: Klavžar, Sandi
Kovse, Matjaz
Powiązania:: https://bibliotekanauki.pl/articles/743784.pdf
Data publikacji:: 2007
Wydawca:: Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:: intersection graph
partial cube
median graph
expansion theorem
Cartesian product of graphs
Opis:: The Θ-graph Θ(G) of a partial cube G is the intersection graph of the equivalence classes of the Djoković-Winkler relation. Θ-graphs that are 2-connected, trees, or complete graphs are characterized. In particular, Θ(G) is complete if and only if G can be obtained from K₁ by a sequence of (newly introduced) dense expansions. Θ-graphs are also compared with familiar concepts of crossing graphs and τ-graphs.
Źródło:: Discussiones Mathematicae Graph Theory; 2007, 27, 2; 313-321
2083-5892
Pojawia się w:: Discussiones Mathematicae Graph Theory
Dostawca treści:: Biblioteka Nauki

Artykuł

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