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By using unramified cohomology groups, we construct a full sequence of cohomological invariants for hermitian forms of any type (orthogonal, symplectic or unitary) that can be used to detect hyperbolicity. The base central simple algebras…

Rings and Algebras · Mathematics 2026-04-02 Yong Hu , Alexandre Lourdeaux

There is a classical geometric construction which uses a binary quadratic form to define an involution on the space of binary d-ics. We give a complete characterization of a general class of such involutions which are definable using…

Algebraic Geometry · Mathematics 2019-03-25 Abdelmalek Abdesselam , Jaydeep Chipalkatti

Modular and quasimodular solutions of specific second order differential equation in the upper-half plane which originates from a study of supersingular j-invariants are given explicitly. A characterization of the differential equation is…

Number Theory · Mathematics 2007-05-23 Masanobu Kaneko , Masao Koike

In this paper, a theory of realization and minimal factorization of rational matrix-valued functions which are $J$-unitary on the imaginary line or on the unit circle is extended to the setting of non-commutative rational formal power…

Functional Analysis · Mathematics 2007-05-23 D. Alpay , D. S. Kalyuzhnyi-Verbovetzkii

H. J. S. Smith proved Fermat's two-square theorem using the notion of palindromic continuants. In this paper we extend Smith's approach to proper binary quadratic form representations in some commutative Euclidean rings, including rings of…

Number Theory · Mathematics 2015-05-28 Charles Delorme , Guillermo Pineda-Villavicencio

Structured canonical forms under unitary and suitable structure-preserving similarity transformations for normal and (skew-)Hamiltonian as well as normal and per(skew)-Hermitian matrices are proposed. Moreover, an algorithm for computing…

Numerical Analysis · Mathematics 2024-03-19 Erna Begovic , Heike Fassbender , Philip Saltenberger

In this thesis new objects to the existing set of invariants of Lie algebras are added. These invariant characteristics are capable of describing the nilpotent parametric continuum of Lie algebras. The properties of these invariants, in…

Mathematical Physics · Physics 2015-06-23 Jiří Hrivnák

We give a rigorous proof of Conjecture 3.1 by Prosen [Prosen T 2010 J. Stat. Mech. $\textbf{2010}$ P07020] on the nilpotent part of the Jordan decomposition of a quadratic fermionic Liouvillian. We also show that the number of the Jordan…

Quantum Physics · Physics 2024-05-27 Shunta Kitahama , Hironobu Yoshida , Ryo Toyota , Hosho Katsura

We provide a coherent picture of our efforts thus far in extending real algebra and its links to the theory of quadratic forms over ordered fields in the noncommutative direction, using hermitian forms and "ordered" algebras with…

Rings and Algebras · Mathematics 2018-04-19 Vincent Astier , Thomas Unger

Let $X$ be a smooth cubic threefold and $J(X)$ be its intermediate Jacobian. We show that there exists a codimension 2 cycle $Z$ on $J(X)\times X$ with $Z_{t}$ homologically trivial for each $t\in J(X)$, such that the morphism $\phi_{Z}:…

Algebraic Geometry · Mathematics 2013-01-01 Ze Xu

We recall the main facts about the odd Laplacian acting on half-densities on an odd symplectic manifold and discuss a homological interpretation for it suggested recently by P. {\v{S}}evera. We study the relationship of odd symplectic…

Differential Geometry · Mathematics 2019-01-08 Hovhannes M. Khudaverdian , Theodore Th. Voronov

Properties of Hermitian forms are used to investigate several natural questions from CR Geometry. To each Hermitian symmetric polynomial we assign a Hermitian form. We study how the signature pairs of two Hermitian forms behave under the…

Complex Variables · Mathematics 2011-10-20 John P. D'Angelo , Jiri Lebl

We give an upper bound for the norm of the determinant of additively indecomposable, totally positive definite quadratic forms defined over the ring of integers of totally real number fields. We apply these results to find lower and upper…

Number Theory · Mathematics 2025-10-10 Magdaléna Tinková , Pavlo Yatsyna

Let g be a complex semisimple Lie algebra and let G' be the Langlands dual group. We give a description of the cohomology algebra of an arbitrary spherical Schubert variety in the loop Grassmannian for G' as a quotient of the form…

Representation Theory · Mathematics 2008-01-09 Victor Ginzburg

Together with David Schlang we computed the discriminants of the invariant Hermitian forms for all indicator $o$ even degree absolutely irreducible characters of the ATLAS groups supplementing the tables of orthogonal determinants computed…

Representation Theory · Mathematics 2025-11-04 Gabriele Nebe

One develops {\em ab initio} the theory of rational/birational maps over reduced, but not necessarily irreducible, projective varieties in arbitrary characteristic. A numerical invariant of a rational map is introduced, called the Jacobian…

Commutative Algebra · Mathematics 2012-03-28 A. V. Dória , S. H. Hassanzadeh , A. Simis

A simple method of constructing a big stock of algebraic varieties with trivial Makar-Limanov invariant is described, the Derksen invariant of some varieties is computed, the generalizations of the Makar-Limanov and Derksen invariants are…

Algebraic Geometry · Mathematics 2011-10-26 Vladimir L. Popov

For quadratic spaces which represent 1 there is a characterization of hermitian compositions in the language of algebras-with-involutions using the even Clifford algebra. We extend this notion to define a generalized composition based on…

Commutative Algebra · Mathematics 2008-09-25 Roland Lötscher

This paper studies two topics concerning on the orthogonal complement of one dimensional subspace with respect to a given quadratic form on a vector space over a number field. One is to determine the invariants for the isomorphism class of…

Number Theory · Mathematics 2018-03-29 Manabu Murata

We discuss the appearance of Jacobi automorphic forms in the theory of superconformal vertex algebras, explaining it by way of supercurves and formal geometry. We touch on related topics such as Ramanujan's differential equations for…

Representation Theory · Mathematics 2016-08-08 Jethro van Ekeren