An n-universal graph is a graph that contains as an induced subgraph a copy of every graph on n vertices It is shown that for each positive integer n > 1 there exists an n-universal graph G on 4" -1 vertices such that G IS a (v, k, A)-graph, and both G and its complement G are l-transitive in the se
Universal graphs and induced-universal graphs
✍ Scribed by Fan R. K. Chung
- Publisher
- John Wiley and Sons
- Year
- 1990
- Tongue
- English
- Weight
- 484 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
We construct graphs that contain all bounded‐degree trees on n vertices as induced subgraphs and have only cn edges for some constant c depending only on the maximum degree. In general, we consider the problem of determining the graphs, so‐called universal graphs (or induced‐universal graphs), with as few vertices and edges as possible having the property that all graphs in a specified family are contained as subgraphs (or induced subgraphs). We obtain bounds for the size of universal and induced‐universal graphs for many classes of graphs such as trees and planar graphs. These bounds are obtained by establishing relationships between the universal graphs and the induced‐universal graphs.
📜 SIMILAR VOLUMES
Let Forb(G) denote the class of graphs with countable vertex sets which do not contain G as a subgraph. If G is finite, 2-connected, but not complete, then Forb(G) has no element which contains every other element of Forb(G) as a subgraph, i.e., this class contains no universal graph.
## Abstract A class of graphs ${\cal C}$ ordered by the homomorphism relation is __universal__ if every countable partial order can be embedded in ${\cal C}$. It is known (see [1,3]) that the class $\cal C\_{k}$ of __k__‐colorable graphs, for any fixed ${k}\geq 3 $, induces a universal partial orde