We define and study a new canonical decomposition of strongly connected graphs that we call the atomic decomposition. We can construct it in linear time from the decomposition in 3-connected components of the considered graph. In a companion article, we use it to characterize, up to homeomorphism, all closed curves in the plane having a given Gauss word.

Symmetries of combinatorial objects are known to complicate search algorithms, but such obstacles can often be removed by detecting symmetries early and discarding symmetric subproblems. Canonical labeling of combinatorial objects facilitates easy equivalence checking through quick matching. All existing canonical labeling software also finds symmetries, but the fastest symmetry-finding softwar...

For n a positive integer and K a finite set of finite algebras, let L(n,K) denote the largest n-generated subdirect product whose subdirect factors are algebras in K. When K is the set of all ngenerated subdirectly irreducible algebras in a locally finite variety V, then L(n,K) is the free algebra FV(n) on n free generators for V. For a finite algebra A the algebra L(n, {A}) is the largest n-ge...

For a connected pasting scheme G, under reasonable assumptions on the underlying category, the category of C-colored G-props admits a cofibrantly generated model category structure. In this paper, we show that, if G is closed under shrinking internal edges, then this model structure on G-props satisfies a (weaker version) of left properness. Connected pasting schemes satisfying this property in...

In graphical modelling, the existence of substantive background knowledge on block ordering of variables is used to perform structural learning within the family of chain graphs (CGs) in which every block corresponds to an undirected graph and edges joining vertices in different blocks are directed in accordance with the ordering.We show that this practice may lead to an inappropriate restricti...

Efficient and accurate path-sensitive analyses pose the challenges of: (a) analyzing an exponentially-increasing number of paths in a control-flow graph (CFG), and (b) checking feasibility of paths in a CFG. We address these challenges by introducing an equivalence relation on the CFG paths to partition them into equivalence classes. It is then sufficient to perform analysis on these equivalenc...

Description A range of tools for social network analysis, including node and graph-level indices, structural distance and covariance methods, structural equivalence detection, p* modeling, and network visualization.

We present a generalization of the so-called σ-game, introduced by Sutner [9], a combinatorial game played on a graph, with relations to cellular automata, as well as odd domination in graphs. A configuration on a graph is an assignment of values in {0, . . . , p− 1} (where p is an arbitrary positive integer) to all the vertices of G. One may think of a vertex v of G as a button the player can ...

We describe Green’s relations on the partition monoid, two of its submonoids, and the related Jones and Brauer monoids. Key Words: partition monoid, Jones monoid, ideal structure 2000 Mathematics Subject Classi…cation: 20M20 1 The partition monoid and some submonoids The elements of the partition monoid Pn [5, 8, 9] are equivalence classes of graphs on a vertex set n [ n0 = f1; 2; :::ng [ f10; ...

To do the text classification on the basis of VSM, and use the maximum common subgraph to measure two graphs’ similarities are the relatively common methods, but these methods have not made full use of lots of semantic information spatial model contained, so the text classification performance is generally poor. In order to improve the classification results of the graph, on the basis of the st...