We solve the design spectrum problem for all theta graphs with 10, 11, 12, 13, 14 and 15 edges.

We propose the notion of {\it resistance of a graph} as an accompanying notion of the structure entropy to measure the force of the graph to resist cascading failure of strategic virus attacks. We show that for any connected network $G$, the resistance of $G$ is $\mathcal{R}(G)=\mathcal{H}^1(G)-\mathcal{H}^2(G)$, where $\mathcal{H}^1(G)$ and $\mathcal{H}^2(G)$ are the one- and two-dimensional s...

Let be any connected graph with vertices set and edges . For two distinct , the detour distance between which is denoted by a longest path in The polynomial of ; defined In this paper, theta uniform will computed.

A theta graph is a homeomorph of K 2;3. In an embedded planar graph the local rotation at one degree-three vertex of a theta graph determines the local rotation at the other degree-three vertex. Using this observation, we give a characterization of planar graphs in terms of balance in an associated signed graph whose vertices are K 1;3 sub-graphs and whose edges correspond to theta graphs.

A Theta graph is a multigraph which is a union of at least three internally disjoint paths that have the same two distinct end vertices. We show full computational complexity characterization of the problem of deciding the existence of a locally injective homomorphism from an input graph G to any fixed Theta graph.

A theta in a graph is an induced subgraph consisting of two nonadjacent vertices joined by three disjoint paths. A prism in a graph is an induced subgraph consisting of two disjoint triangles joined by three disjoint paths. This paper gives a polynomial-time algorithm to test whether a graph has an induced subgraph that is either a prism or a theta.

Inspired by a question of Lovász, we introduce a hierarchy of nested semidefinite relaxations of the convex hull of real solutions to an arbitrary polynomial ideal, called theta bodies of the ideal. For the stable set problem in a graph, the first theta body in this hierarchy is exactly Lovász’s theta body of the graph. We prove that theta bodies are, up to closure, a version of Lasserre’s rela...

Inspired by a question of Lovász, we introduce a hierarchy of nested semidefinite relaxations of the convex hull of real solutions to an arbitrary polynomial ideal, called theta bodies of the ideal. For the stable set problem in a graph, the first theta body in this hierarchy is exactly Lovász’s theta body of the graph. We prove that theta bodies are, up to closure, a version of Lasserre’s rela...