Transversal structures (also known as regular edge labelings) are combinatorial structures defined over 4-connected plane triangulations with quadrangular outer-face. They have been intensively studied and used for many applications (drawing algorithm, random generation, enumeration. . . ). In this paper we introduce and study a generalization of these objects for the toroidal case. Contrary to...

The asymptotic number (of isomorphism classes) of toroidal maps of type (3; 6) with at most n vertices is found, together with the fraction of those with multiplicity 1. Accurate lower and upper asymptotic estimates are provided for the number of toroidal maps of type (3; 6) with a Hamiltonian normal cycle and with at most n vertices. The case of type (6; 3) toroidal maps follows by duality. Si...

Geometrical and topological properties of the quasi-plane Szekeres model and of the plane symmetric dust model are discussed. Some related comments on the quasihyperbolical model are made. These properties include: (1) The pattern of expansion in the plane symmetric case, and the Newtonian model that imitates it; (2) The possibility of toroidal topology of the t = const sections in the plane sy...

The goal of magnetic confinement devices such as tokamaks is to produce energy from nuclear fusion reactions in plasmas at low densities and high temperatures. Experimentally, toroidal flows have been found to significantly improve the energy confinement, and therefore the performance of the machine. As extrinsic momentum sources will be limited in future fusion devices such as ITER, an underst...

The tenacity of a graph G, T(G), is dened by T(G) = min{[|S|+τ(G-S)]/[ω(G-S)]}, where the minimum is taken over all vertex cutsets S of G. We dene τ(G - S) to be the number of the vertices in the largest component of the graph G - S, and ω(G - S) be the number of components of G - S.In this paper a lower bound for the tenacity T(G) of a graph with genus γ(G) is obtained using the graph's connec...

Let X be any variety in characteristic zero. V?X an open subset that has toroidal singularities. We show the existence of a canonical desingularization except for V. It is morphism f:Y?X, which does not modify V and transforms into embedding Y, with singularities extending those on Moreover, exceptional divisor simple normal crossings Y. The theorem naturally generalizes Hironaka desingularizat...

Many effects influence toroidal flow evolution in tokamak plasmas. Momentum sources and radial transport due to collisional processes and microturbulence-induced anomalous transport are usually considered. In addition, toroidal flow can be affected by non-axisymmetric magnetic fields; resonant components cause localized electromagnetic toroidal torques near rational surfaces in flowing plasmas ...

A parametric study of electromagnetic effects on toroidal momentum transport has been performed. The work is based on a new version of the Weiland model where symmetry breaking toroidicity effects derived from the stress tensor have been taken into account. The model includes a self-consistent calculation of the toroidal momentum diffusivity, which contains both diagonal and off-diagonal contri...

Introduction Different kinds of tokamak experiments have been done where the plasma rotates mainly in the toroidal direction. Rotation has been induced by e.g. neutral beam injection (NBI). Furthermore, in astrophysics the plasma in accretion disks also rotates mainly in the toroidal direction. We present the newly developed spectral code PHOENIX which makes use of the JacobiDavidson subspace i...

Plasmonic toroidal resonance has attracted growing interests because of its low loss electromagnetic properties and potential high sensitive nanophotonic applications. However, the realization in a metamaterial requires three-dimensional complicated structural design so far. In this paper, we design a simple metal-dielectric-metal (MIM) sandwich nanostructure, which exhibits a strong toroidal d...