A graph is Gaussian if it is the graph of arcs and self-intersections of a closed C∞ curve in the plane. In this note we describe a recursive characterization of 4-regular Gaussian graphs and give conditions under which the Gaussian property is a graph invariant.

Higher dimensional automata, i.e. labelled precubical sets, model concurrent systems. We introduce the homology graph of an HDA, which is a directed graph whose nodes are the homology classes of the HDA. We show that the homology graph is invariant under homeomorphic abstraction, i.e. under weak morphisms that are homeomorphisms.

We consider the problem of characterizing the finitely additive probability measures on the definable subsets of the random graph which are invariant under the action of the automorphism group of this graph. We show that such measures are all integrals of Bernoulli measures (which arise from the coin-flipping model of the construction of the random graph). We also discuss generalizations to oth...

The minor crossing number of a graph G, mcr(G), is defined as the minimum crossing number of all graphs that contain G as a minor. We present some basic properties of this new minor-monotone graph invariant. We give estimates on mcr for some important graph families using the topological structure of graphs satisfying mcr(G) ≤ k.

We propose a precise definition of a continuous time dynamical system made up of interacting open subsystems. The interconnections of subsystems are coded by directed graphs. We prove that the appropriate maps of graphs called graph fibrations give rise to maps of dynamical systems. Consequently surjective graph fibrations give rise to invariant subsystems and injective graph fibrations give ri...

We consider the averaging principle for deterministic and stochastic systems with a fast component (family of continuous time Markov chains depending on state system as parameter). show that, due to nontrivial structure simplex invariant probability measures chains, limiting should be considered graph certain gluing conditions at vertices graph.

The sum of distances between all pairs of vertices W (G) in a connected graph G as a graph invariant was first introduced by Wiener [9] in 1947. He observed a correlation between boiling points of paraffins and this invariant, which has later become known as Wiener index of a graph. Today, the Wiener index is one of the most widely used descriptors in chemical graph theory. Due to its strong co...

Abstract We study the invariance of KMS states on graph $C^{\ast }$ -algebras coming from strongly connected and circulant graphs under classical quantum symmetry graphs. show that unique state for is invariant automorphism group graph. For graphs, it shown action groups preserves only one occurring at critical inverse temperature. also give an example a -algebra having more than such all them ...

Considering systems of separations in a graph that separate every pair of a given set of vertex sets that are themselves not separated by these separations, we determine conditions under which such a separation system contains a nested subsystem that still separates those sets and is invariant under the automorphisms of the graph. As an application, we show that the k-blocks – the maximal verte...

Let T be a torus of dimension n > 1 and M a compact T -manifold. M is a GKM manifold if the set of zero dimensional orbits in the orbit space M/T is zero dimensional and the set of one dimensional orbits in M/T is one dimensional. For such a manifold these sets of orbits have the structure of a labelled graph and it is known that a lot of topological information about M is encoded in this graph...