We present BigSparse, a fully external graph analytics system that picks up where semi-external systems like FlashGraph and X-Stream, which only store vertex data in memory, left off. BigSparse stores both edge and vertex data in an array of SSDs and avoids random updates to the vertex data, by first logging the vertex updates and then sorting the log to sequentialize accesses to the SSDs. This...

let z2 = {0, 1} and g = (v ,e) be a graph. a labeling f : v → z2 induces an edge labeling f* : e →z2 defined by f*(uv) = f(u).f (v). for i ε z2 let vf (i) = v(i) = card{v ε v : f(v) = i} and ef (i) = e(i) = {e ε e : f*(e) = i}. a labeling f is said to be vertex-friendly if | v(0) − v(1) |≤ 1. the vertex balance index set is defined by {| ef (0) − ef (1) | : f is vertex-friendly}. in this paper ...

The neighborhood of a pair of vertices u, v in a triple system is the set of vertices w such that uvw is an edge. A triple system H is semi-bipartite if its vertex set contains a vertex subset X such that every edge of H intersects X in exactly two points. It is easy to see that if H is semi-bipartite, then the neighborhood of every pair of vertices in H is an independent set. We show a partial...

We give a fixed-parameter tractable (FPT) approximation algorithm computing the pathwidth of a tournament, and more generally, of a semi-complete digraph. Based on this result, we prove the following. • The Topological Containment problem is FPT on semi-complete digraphs. More precisely, given a semi-complete n-vertex digraph T and a digraph H, one can check in time f(|H|)n log n, where f is so...

An (f, g)-semi-matching in a bipartite graph G = (U ∪V,E) is a set of edges M ⊆ E such that each vertex u ∈ U is incident with at most f(u) edges of M , and each vertex v ∈ V is incident with at most g(v) edges of M . In this paper we give an algorithm that for a graph with n vertices and m edges, n ≤ m, constructs a maximum (f, g)semi-matching in running time O(m ·min( √∑ u∈U f(u), √∑ v∈V g(v)...

A graph is semi-symmetric if it is regular and edge transitive but not vertex transitive. The 3and 4-valent semi-symmetric graphs are wellstudied. Several papers describe infinite families of such graphs and their properties. 3-valent semi-symmetric graphs have been completely classified up to 768 vertices. The goal of this project is to extend this work to 5-valent semi-symmetric graphs. In th...

We discuss the calculation of semi-classical wormhole vertex operators from wave functions which satisfy the Wheeler-deWitt equation and momentum constraints, together with certain ‘wormhole boundary conditions’. We consider a massless minimally coupled scalar field, initially in the spherically symmetric ‘mini-superspace’ approximation, and then in the ‘midi-superspace’ approximation, where no...