Báo cáo toán học: "Bound Graph Polysemy" ppt

... the same class. In general, a poset realizes two graphs simultaneously: one is its upper bound graph and another, its lower bound graph. These graphs may be thought of as two meanings of the poset, ... characterization of upper bound graphs, Congr. Numer. 40 (1983), 189–193. [6] J. R. Lundgren, J. S. Maybee, and F. R. McMorris, Two -graph inversion of competition graphs and upper bound gr...

Ngày tải lên: 07/08/2014, 06:20

... to hear about your corrections, updates and comments! Related bibliographies on the web are: • Bibliography of signed and gain graphs, by Thomas Zaslavsky, published as a dynamic survey DS8 in ... of directed graphs:ifD=(V,A) is a finite directed graph (with vertex set V = {0, 1, 2, ,r} and arc set A = {a 1 , ,a n }⊆V 2 ), then one has the obvious “directed circuits” in the digraph that ......

Ngày tải lên: 07/08/2014, 05:23

... p) of graphs on a fixed vertex set V .In this context an up-set (down-set) is just a monotone increasing (decreasing) property of graphs on V .Note that we shall not distinguish sets A of graphs ... set of graphs S on V such that xy /∈ S and S ∪{xy} is isomorphic to H.LetU H (G p ,x,y) be the union of all subgraphs S of G p with S ∈H(x, y), and let X H (G p ,x,y)bethe number of such subgraphs...

Ngày tải lên: 07/08/2014, 06:20

... distinguished outer face have been adjoined to give a graph H which nicely decomposes into a graph G and a weighted directed graph F. determine a matching of the graph in Figure 5. The weight of the matching ... matchings of some “locally symmetric” finite planar graphs, that is, graphs that arise as finite induced subgraphs of highly symmetric infinite planar graphs. Lastly, in § 7wegiv...

Ngày tải lên: 07/08/2014, 06:20

... focus on not strongly connected graphs. More precisely, we compute the homotopy type of the complex of not strongly connected subgraphs of a directed graph, if the graph belongs to a particular ... graphs have been studied. Although most papers have dealt with complexes of all graphs having a particular property P , it is indeed natural to study the complex of all subgraphs of a given gra...

Ngày tải lên: 07/08/2014, 08:22

... 05C15 Abstract An H-factor of a graph G is a spanning subgraph of G whose connected com- ponents are isomorphic to H. Given a properly edge-colored graph G,arainbow H-subgraph of G is an H-subgraph of G whose ... H-factor whose components are rainbow H-subgraphs. The follow- ing result is proved. If H is any fixed graph with h vertices then every properly edge-colored graph with hn ver...

Ngày tải lên: 07/08/2014, 13:21

... determining set if and only if every vertex in the graph can be uniquely identified by its own graph properties and its relationship to the vertices in S. Every graph has a determining set. Trivially the ... disjointness and nondisjointness; thus they induce graph automorphisms of K n:k . The Erd˝os-Ko-Rado Theorem shows that all automorphisms of Kneser graphs arise in this way [5]. Th...

Ngày tải lên: 07/08/2014, 13:21

... cycles. J. Graph Theory, 55(3):249–265, 2007. [8] Xuding Zhu. Circular choosability of graphs. J. Graph Theory, 48(3):210–218, 2005. [9] Xuding Zhu. Recent developments in circular colouring of graphs. ... description of typical induced subgraphs of graphs with the heart non-empty and distinct from an odd cycle follows immediately from Lemma 5. Corollary 6. Let G be a connected graph su...

Ngày tải lên: 07/08/2014, 21:20

... sequel.) We will call such graphs admissible weighted graphs. One can define a natural metric on an admissible weighted graph [4] and then the Gromov-Hausdorff distance between such graphs makes sense. ... 51F99 Abstract Positively weighted graphs have a natural intrinsic metric. We consider finite, positively weighted graphs with a positive lower bound for their minimal weights and show that...

Ngày tải lên: 07/08/2014, 21:21

... that the graph G is a near threshold graph (or NT graph for short) if Λ(G) and D ∗ (G) agree in n − 2 places. We note in passing that it straightforward to show that a graph G is an NT graph if ... subgraphs. Finally we also note that (O 2 ∪ (K 2 ∨ P 4 ) ∪ K 2 )) ∨ O 2 contains each of P 4 , C 4 , and 2K 2 as induced subgraphs. Hence, we see that an NT graph may contain as induced...

Ngày tải lên: 07/08/2014, 21:21