Eulerian numbers (and “Alternate Eulerian numbers”) are often interpreted as distributions of statistics defined over the Symmetric group. The main purpose of this paper is to define a way to represent permutations that provides some other combinatorial interpretations of these numbers. This representation uses a one-to-one correspondence between permutations and the so-called subexceedant func...

An attractive approach for simulation of large deformation solid dynamics is to combine Eulerian nite diierencing with material interface tracking. The Eulerian computational mesh is not subject to mesh distortion, and tracking eliminates spurious numerical diiusion at interfaces and the need for mixed-material computational cells. We have developed such an approach within the framework of the ...

Potentially this paper contains some results that may be of interest to NPG, but not in its present form. The main issue is that the authors describe the method of Lagrangian descriptors in a variety of misleading and wrong ways, and they also have neglected to mention a large amount of relevant literature. The authors develop a new Lagrangian descriptor based on integrating the magnitude of th...

Downward turbulent bubbly flows in pipes were modeled using computational fluid dynamics tools. The Hydrodynamics, phase distribution and turbulent structure of twophase air-water flow in a 57.15 mm diameter and 3.06 m length vertical pipe was modeled by using the 3-D Eulerian-Eulerian multiphase flow approach. Void fraction, liquid velocity and turbulent fluctuations profiles were calculated a...

The combinatorial Hopf algebra on building sets BSet extends the chromatic Hopf algebra of simple graphs. The image of a building set under canonical morphism to quasi-symmetric functions is the chromatic symmetric function of the corresponding hypergraph. By passing from graphs to building sets, we construct a sequence of symmetric functions associated to a graph. From the generalized DehnSomm...

The spatial dependence of Lagrangian displacement and velocity statistics is studied in the context of a data assimilating numerical model of the Gulf Mexico. In the active eddy region of the Western Gulf, a combination of Eulerian and Lagrangian measures are used to locate strongly hyperbolic regions of the flow. The statistics of the velocity field sampled by sets of drifters launched specifi...

Arbitrary Lagrangian Eulerian (ALE) methods have existed for several decades. However, three-dimensional multi-material arbitrary Lagrangian Eulerian (MMALE) methods for unstructured grids are relatively new. MMALE algorithms provide the framework to model sections of a simulation as either Lagrangian, ALE, or Eulerian. In addition, sections of a simulation can switch in time between mesh motio...

Let G = (V, A) be an Eulerian directed graph with an arclabeling. In this work we study the problem of finding an Eulerian circuit of lexicographically minimal label among all Eulerian circuits of the graph. We prove that this problem is NP-hard by showing a reduction from the Directed-Hamiltonian-Circuit problem. If the labeling of the arcs is such that arcs going out from the same vertex have...

Stembridge, J.R., Eulerian numbers, tableaux, and the Betti numbers of a toric variety, Discrete Mathematics 99 (1992) 307-320. Let Z denote the Coxeter complex of S,, and let X(X) denote the associated toric variety. Since the Betti numbers of the cohomology of X(Z) are Eulerian numbers, the additional presence of an &-module structure permits the definition of an isotypic refinement of these ...