The interval number of a graph G, denoted i(G), is the least positive integer t such that G is the intersection graph of sets, each of which is the union of t compact real intervals. It is known that every planar graph has interval number at most 3 and that this result is best possible. We investiga
Graphs of given genus and arbitrarily large maximum genus
β Scribed by Richard D. Ringeisen
- Publisher
- Elsevier Science
- Year
- 1973
- Tongue
- English
- Weight
- 540 KB
- Volume
- 6
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
β¦ Synopsis
Abstrart. The maximum genus of a connected graph (: is the maximum among the genera of a!1 cornpact olientable 2-manifolds upon which G has 2-&l embeddings. In the theorems that fc-llow the use of an edg;:-adding techniq se is combined with ihe well-known Edmonds' technique to prfiruce the desired results. Planar graphs of arbitrarily large maximum genus are disrlayed in Theorem 1. Theorem 2 shows that the possibililty for arbitrarily large difference be-tlMeon genus and maximu>n genus is not limited to planar graphs. In particular, we show that the l):QeeY grqph, the standard maximal planar graph, and the prism graph are upper embeddable. We then show that given ~VZ akld n, there is a graph of genus n and maximum genus larger ihnn mn.
π SIMILAR VOLUMES
The maximum genus of all vertex-transitive graphs is computed. It is proved that a k-valent vertex-transitive graph of girth g is upper-embeddable whenever k 3 4 or g 2 4. Non-upper-embeddable vertex-transitive graphs are characterized. A particular attention is paid to Cayley graphs. Groups for wh
Skoviera, M., The maximum genus of graphs of diameter two, Discrete Mathematics 87 (1991) 175-180. Let G be a (finite) graph of diameter two. We prove that if G is loopless then it is upper embeddable, i.e. the maximum genus y,&G) equals [fi(G)/Z], where /3(G) = IF(G)1 -IV(G)1 + 1 is the Betti numbe
This paper shows that a simple graph which can be cellularly embedded on some closed surface in such a way that the size of each face does not exceed 7 is upper embeddable. This settles one of two conjectures posed by Nedela and S8 koviera (1990, in ``Topics in Combinatorics and Graph Theory,'' pp.
## Abstract Some of the early questions concerning the maximum genus of a graph have now been answered. In this paper we survey the progress made on such problems and present some recent results, outlining proofs for some of the major theorems.