• Title/Summary/Keyword: infinite graph

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CHARACTERIZATION THEOREMS FOR CERTAIN CLASSES OF INFINITE GRAPHS

  • Jung, Hwan-Ok
    • Journal of applied mathematics & informatics
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    • v.30 no.1_2
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    • pp.245-252
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    • 2012
  • In this paper we present a necessary and sufficient conditions for an infinite VAP-free plane graph to be a 3LV-graph as well as an LV-graph. We also introduce and investigate the concept of the order and the kernel of an infinite connected graph containing no one-way infinite path.

STRUCTURAL PROPERTIES FOR CERTAIN GLASSES OF INFINITE PLANAR GRAPHS

  • Jung, Hwan-Ok
    • Journal of applied mathematics & informatics
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    • v.13 no.1_2
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    • pp.105-115
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    • 2003
  • An infinite locally finite plane graph is called an LV-graph if it is 3-connected and VAP-free. If an LV-graph G contains no unbounded faces, then we say that G is a 3LV-graph. In this paper, a structure theorem for an LV-graph concerning the existence of a sequence of systems of paths exhausting the whole graph is presented. Combining this theorem with the early result of the author, we obtain a necessary and sufficient conditions for an infinite VAP-free planar graph to be a 3LV-graph as well as an LV-graph. These theorems generalize the characterization theorem of Thomassen for infinite triangulations.

EXISTENCE OF SPANNING 3-TREES IN A 3-CONNECTED LOCALLY FINITE VAP-FREE PLANE GRAPH

  • Jung, Hwan-Ok
    • Journal of applied mathematics & informatics
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    • v.28 no.3_4
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    • pp.893-908
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    • 2010
  • In this paper we prove the existence of spanning 3-trees in a 3-connected infinite locally finite VAP-free plane graph. Together with the results of Barnette and the author, this yields that every finite or infinite 3-connected locally finite VAP-free plane graph contains a spanning 3-tree.

KAZDAN-WARNER EQUATION ON INFINITE GRAPHS

  • Ge, Huabin;Jiang, Wenfeng
    • Journal of the Korean Mathematical Society
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    • v.55 no.5
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    • pp.1091-1101
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    • 2018
  • We concern in this paper the graph Kazdan-Warner equation $${\Delta}f=g-he^f$$ on an infinite graph, the prototype of which comes from the smooth Kazdan-Warner equation on an open manifold. Different from the variational methods often used in the finite graph case, we use a heat flow method to study the graph Kazdan-Warner equation. We prove the existence of a solution to the graph Kazdan-Warner equation under the assumption that $h{\leq}0$ and some other integrability conditions or constrictions about the underlying infinite graphs.

A STRUCTURE THEOREM AND A CLASSIFICATION OF AN INFINITE LOCALLY FINITE PLANAR GRAPH

  • Jung, Hwan-Ok
    • Journal of applied mathematics & informatics
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    • v.27 no.3_4
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    • pp.531-539
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    • 2009
  • In this paper we first present a structure theorem for an infinite locally finite 3-connected VAP-free planar graph, and in connection with this result we study a possible classification of infinite locally finite planar graphs by reducing modulo finiteness.

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SPANNING 3-FORESTS IN BRIDGES OF A TIGHT SEMIRING IN AN LV-GRAPH

  • Jung, Hwan-Ok
    • Journal of applied mathematics & informatics
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    • v.27 no.5_6
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    • pp.1307-1318
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    • 2009
  • An infinite locally finite plane graph is an LV-graph if it is 3-connected and VAP-free. In this paper, as a preparatory work for solving the problem concerning the existence of a spanning 3-tree in an LV-graph, we investigate the existence of a spanning 3-forest in a bridge of type 0,1 or 2 of a tight semi ring in an LV-graph satisfying certain conditions.

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EXISTENCE OF SPANNING 4-SUBGRAPHS OF AN INFINITE STRONG TRIANGULATION

  • Jung, Hwan-Ok
    • Journal of applied mathematics & informatics
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    • v.26 no.5_6
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    • pp.851-860
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    • 2008
  • A countable locally finite triangulation is a strong triangulation if a representation of the graph contains no vertex- or edge-accumulation points. In this paper we exhibit the structure of an infinite strong triangulation and prove the existence of connected spanning subgraph with maximum degree 4 in such a graph

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5-CYCLABILITY IN INFINITE PLANAR GRAPHS

  • JUNG HWAN-OK
    • Journal of applied mathematics & informatics
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    • v.19 no.1_2
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    • pp.537-543
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    • 2005
  • A graph is k-cyclable if given k vertices there is a cycle that contains the k vertices. Sallee showed that every finite 3-connected planar graph is 5-cyclable. In this paper Sallee's result is extended to 3-connected infinite locally finite VAP-free plane graphs containing no unbounded faces.

[2,3]-FACTORS IN A 3-CONNECTED INFINITE PLANAR GRAPH

  • Jung, Hwan-Ok
    • Journal of applied mathematics & informatics
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    • v.10 no.1_2
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    • pp.27-40
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    • 2002
  • For two integers m, n with m $\leq$ n, an [m,n]-factor F in a graph G is a spanning subgraph of G with m $\leq$ d$\_$F/(v) $\leq$ n for all v ∈ V(F). In 1996, H. Enomoto et al. proved that every 3-connected Planar graph G with d$\_$G/(v) $\geq$ 4 for all v ∈ V(G) contains a [2,3]-factor. In this paper. we extend their result to all 3-connected locally finite infinite planar graphs containing no unbounded faces.

AN EXTENSION OF SALLEE'S THEOREM TO INFINITE LOCALLY FINITE VAP-FREE PLANE GRAPHS

  • Jung Hwan-Ok
    • Journal of applied mathematics & informatics
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    • v.22 no.1_2
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    • pp.83-93
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    • 2006
  • A graph is k-cyclable if given k vertices there is a cycle that contains the k vertices. Sallee showed that every finite 3-connected planar graph is 5-cyclable. In this paper, by characterizing the circuit graphs and investigating the structure of LV-graphs, we extend his result to 3-connected infinite locally finite VAP-free plane graphs.