Sequences of discrete Levy and adjoint Levy transformations for the multidimensional quadrilateral lattices are studied. After a suitable number of iterations we show how all the relevant geometrical features of the transformed quadrilateral lattice can be expressed in terms of multi-Casorati determinants. As an example we dress the Cartesian lattice. On leave of absence from Beijing Graduate S...

We review and prove a total of ten different formulas for the area of a bicentric quadrilateral. Our main result is that this area is given by

The flux reconstruction (FR) approach to high-order methods has proved to be a promising alternative to traditional discontinuous Galerkin (DG) schemes since they facilitate the adoption of explicit time-stepping methods suitable for parallel architectures like GPUs. The FR approach provides a parameterized family of schemes through which various classical schemes like nodal-DG and spectral dif...

In this paper, we introduce a new family of mixed finite element spaces of higher order (k ≥ 1) on general quadrilateral grids. A typical element has two fewer degrees of freedom than the well-known RaviartThomas finite element RT[k], yet enjoys an optimal-order approximation for the velocity in L 2-norm. The order of approximation in the divergence norm is one less than the velocity, as is com...

It is known from a result of Prautzsch and Reif [19] that it is impossible to construct a flexible C2 scheme over extraordinary vertices unless the regular subdivision scheme (assumed in [19] to be based on polynomial splines) is capable of producing polynomial patches of total degree 8 in the triangle case and bi-degree 6 in the quadrilateral case. Prautzsch-Reif’s degree estimate, however, co...

Schneiders and Debye (1995) present two algorithms for quadrilateral mesh refinement. These algorithms refine quadrilateral meshes while maintaining mesh conformity. The first algorithm maintains conformity by introducing triangles. The second algorithm maintains conformity without triangles, but requires a larger degree of refinement. Both algorithms introduce nodes with non-optimal valences. ...

Abstract. This paper describes a quadrilateral mesh generation algorithm ideally suited for transition subdomain meshes in the context of any domain decomposition meshing strategy. The algorithm is based on an automatic hierarchical region decomposition in which, in the last level, it is possible to generate quadrilateral elements with a conventional mapping strategy. In two dimensions, a subdo...

Several promising approaches for hexahedral mesh generation work as follows: Given a prescribed quadrilateral surface mesh they first build the combinatorial dual of the hexahedral mesh. This dual mesh is converted into the primal hexahedral mesh, and finally embedded and smoothed into the given domain. Two such approaches, the modified whisker weaving algorithm by Folwell and Mitchell, as well...

in this paper, two new quadrilateral elements are formulated to solve plane problems. low sensitivity to geometric distortion, no parasitic shear error, rotational invariance, and satisfying the felippa pure bending test are characteristics of these suggested elements. one proposed element is formulated by establishing equilibrium equations for the second-order strain field. the other suggested...