Let \(G\) act transitively on incident vertex, edge pairs of the connected 4-valent graph \(\Gamma\). If a normal subgroup \(N\) does not give rise to a natural 4-valent quotient \(\Gamma_{N}\) with \(G / N\) acting transitively on incident vertex, edge pairs, then either (a) \(N\) has just one or t
4-valent graphs
β Scribed by T. C. Enns
- Publisher
- John Wiley and Sons
- Year
- 1982
- Tongue
- English
- Weight
- 707 KB
- Volume
- 6
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
β¦ Synopsis
Let bk}k22, k+4 be a sequence of non-negative integers which satisfies 8 + &(k -4)pk = 0. Then there exists an integer p4 such that there exists a 2-connected planar graph with exactly pk k-gons as faces for all k 1 2 . This paper determines all such p4 when pk = 0 f o r k 1 5 and determines that there is a constant C 2 1 such that for some rn 5 pz +ap3 + C, there exists a 2connected planar graph with exactly pk faces for each p 4 = m + 2 w , w a positive integer. When there exists at least one odd k 1 3 for which pk # 0, the coefficient 2 of w in the above equation may be replaced by 1. These conclusions do not hold if the coefficients of p2 and p J are any smaller than 1 and i, respectively.
π SIMILAR VOLUMES
Let \(\Gamma\) be a connected, 4-valent, \(G\)-symmetric graph. Each normal subgroup \(N\) of \(G\) gives rise to a natural symmetric quotient \(\Gamma_{N}\), the vertices of which are the \(N\)-orbits on \(V \Gamma\). If this quotient \(\Gamma_{N}\) is not itself 4-valent, then it was shown in [1]
A graph is said to be 1 2 -transitive if its automorphism group acts transitively on vertices and edges but not on arcs. For each n 11, a 1 2 -transitive graph of valency 4 and girth 6, with the automorphism group isomorphic to A n \_Z 2 , is given.
We investigate locally grid graphs. The main results are (i) a characterization of the Johnson graphs (and certain quotients of these) as locally grid graphs such that two points at distance 2 have precisely four common neighbors, and (ii) a complete determination of all graphs that are locally a 4
We construct a family of 4-chromatic graphs which embed on the projective plane, and characterize the edge-critical members. The family includes many well known graphs, and also a new sequence of graphs, which serve to improve Gallai's bound on the length of the shortest odd circuit in a 4-chromatic