A non-singular sesquilinear form is constructed that is preserved by the Lawrence-Krammer representation. It is shown that if the polynomial variables q and t of the Lawrence-Krammer representation are chosen to be appropriate algebraically independant unit complex numbers, then the form is negativedefinite Hermitian. Unitary matrices diagonalize, and it is shown that the eigenvalues of a Lawre...

This paper is concerned with the computation of 3D vertex singularities of anisotropic elastic fields. The singularities are described by eigenpairs of a corresponding operator pencil on a subdomain of the sphere. The solution approach is to introduce a modified quadratic variational boundary eigenvalue problem which consists of two self-adjoint, positive definite sesquilinear forms and a skew-...

In this paper we investigate a class of combined discrete-continuous mechanical systems consisting of a continuous elastic structure and a nite number of concentrated masses, elastic supports and linear oscillators of arbitrary dimension. After the motion equations for such combined systems are derived, they are formulated as an abstract evolution equation on an appropriately deened Hilbert spa...

We study decompositions of operator measures and more general sesquilinear form measures E into linear combinations of positive parts, and their diagonal vector expansions. The underlying philosophy is to represent E as a trace class valued measure of bounded variation on a new Hilbert space related to E. The choice of the auxiliary Hilbert space fixes a unique decomposition with certain proper...

Let G be the group preserving a nondegenerate sesquilinear form B on a vector space V , and H a symmetric subgroup of G of the type G1 × G2. We explicitly parameterize the H-orbits in GrG(r), the Grassmannian of r-dimensional isotropic subspaces of V , by a complete set of H-invariants. We describe the Bruhat order in terms of the majorization relationship over a diagram of these H-invariants. ...

We prove that the complex of proper non-trivial non-degenerate subspaces of a finitedimensional vector space endowed with a non-degenerate sesquilinear form is homotopy equivalent to a wedge of spheres. Additionally, we show that the same is true for a slightly wider class of simplicial complexes, the so-called generalized Phan geometries of type An. These generalized Phan geometries occur as r...

This work is devoted to a study and summary of different Infinite Element (IE) formulations for Helmholtz problems in arbitrary exterior domains. The theoretical setting for each of the different formulations is presented and related to the mathematical existence theory. The influences of a bilinear or a sesquilinear formulation are discussed as well as possible extensions to other elements. Th...

We study two seminal approaches, developed by B. Simon and J. Kisy\'nski, to the well-posedness of Schr\"odinger equation with a time-dependent Hamiltonian. In both cases Hamiltonian is assumed be semibounded from below have constant form domain but possibly non-constant operator domain. The problem addressed in abstract setting, without assuming any specific functional expression for connectio...

This paper develops some interior penalty hp-discontinuous Galerkin (hp-DG) methods for the Helmholtz equation in two and three dimensions. The proposed hp-DG methods are defined using a sesquilinear form which is not only mesh-dependent but also degree-dependent. In addition, the sesquilinear form contains penalty terms which not only penalize the jumps of the function values across the elemen...