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Positive operator measures (with values in the space of bounded operators on a Hilbert space) and their generalizations, mainly positive sesquilinear form measures, are considered with the aim of providing a framework for their generalized…

Functional Analysis · Mathematics 2015-06-26 Tuomas Hytönen , Juha-Pekka Pellonpää , Kari Ylinen

We consider second-order partial differential operators $H$ in divergence form on $\Ri^d$ with a positive-semidefinite, symmetric, matrix $C$ of real $L_\infty$-coefficients and establish that $H$ is strongly elliptic if and only if the…

Analysis of PDEs · Mathematics 2007-05-23 A. F. M. ter Elst , Derek W. Robinson , Yueping Zhu

We define the concept of an affinized projective variety and show how one can, in principle, obtain q-identities by different ways of computing the Hilbert series of such a variety. We carry out this program for projective varieties…

Mathematical Physics · Physics 2009-10-31 Peter Bouwknegt

To develop a unitary quantum theory with probabilistic description for pseudo- Hermitian systems one needs to consider the theories in a different Hilbert space endowed with a positive definite metric operator. There are different…

Quantum Physics · Physics 2013-05-10 Ananya Ghatak , Bhabani Prasad Mandal

In this paper, we give a new generalization of positive sectional curvature called positive weighted sectional curvature. It depends on a choice of Riemannian metric and a smooth vector field. We give several simple examples of Riemannian…

Differential Geometry · Mathematics 2014-10-08 Lee Kennard , William Wylie

The purpose of this article is to give a short introduction to the concept of quasi-unitary equivalence of quadratic forms and its consequences. In particular, we improve an estimate concerning the transitivity of quasi-unitary equivalence…

Spectral Theory · Mathematics 2025-03-31 Olaf Post , Jan Simmer

We introduce three notions of partial bihamiltonian structures ($\operatorname{PQ}$, $\operatorname{PN}$ et $\operatorname{P\Omega}$) in the convenient setting defined by Fr\"{o}licher, Kriegl and Michor. We study geometrical objects linked…

Differential Geometry · Mathematics 2024-08-06 Patrick Cabau , Fernand Pelletier

Unitarity is a cornerstone of quantum theory, ensuring the conservation of probability and information. Although non-Hermitian Hamiltonians are typically associated with open or dissipative systems, pseudo-Hermitian quantum mechanics shows…

High Energy Physics - Theory · Physics 2025-11-03 Ruifeng Leng , Cheng-Yang Lee , Siyi Zhou

We present a general formalism for giving a measure space paired with a separable Hilbert space a quantum version based on normalized positive operator-valued measure. The latter are built from families of density operators labelled by…

Quantum Physics · Physics 2019-11-06 Jean Pierre Gazeau , Barbara Heller

In this work an observation concerning a positivity property of the quantum anharmonic oscillator is made. This positivity property is suggested by the BMV conjecture.

Classical Analysis and ODEs · Mathematics 2014-10-22 Victor Katsnelson

Two semimetrics on probability distributions are proposed, given as the sum of differences of expectations of analytic functions evaluated at spatial or frequency locations (i.e, features). The features are chosen so as to maximize the…

Machine Learning · Statistics 2016-10-31 Wittawat Jitkrittum , Zoltan Szabo , Kacper Chwialkowski , Arthur Gretton

In this talk we go over several new developments regarding the techniques for a large class of non-hermitian matrix models with unitary randomness (complex random numbers). In particular, we discuss: (a) - A diagrammatic approach based on a…

High Energy Physics - Phenomenology · Physics 2008-02-03 Romuald A. Janik , Maciej A. Nowak , Gabor Papp , Ismail Zahed

In the general theory of quantum measurement, one associates a positive semidefinite operator on a $d$-dimensional Hilbert space to each of the $n$ possible outcomes of an arbitrary measurement. In the special case of a projective…

Quantum Physics · Physics 2021-11-23 Yizhou Liu , John B. DeBrota

We revisit Bressoud's generalized Borwein conjecture. Making use of new positivity-preserving transformations for q-binomial coefficients we establish the truth of infinitely many cases of the Bressoud conjecture. In addition, we prove new…

Number Theory · Mathematics 2020-06-23 Alexander Berkovich

This work introduces a novel framework of uniform realizability that unifies and generalizes various realizability interpretations of logic, particularly focussing on the treatment of atomic formulas and quantifiers. Traditional…

Logic in Computer Science · Computer Science 2026-03-05 Ulrich Berger , Paulo Oliva

We discuss positivity properties of `distinguished propagators', i.e. distinguished inverses of operators that frequently occur in scattering theory and wave propagation. We relate this to the work of Duistermaat and H\"ormander on…

Analysis of PDEs · Mathematics 2014-11-27 András Vasy

We obtain generalisations of some inequalities for positive unital linear maps on matrix algebra. This also provides several positive semidefinite matrices and we get some old and new inequalities involving the eigenvalues of a Hermitian…

Functional Analysis · Mathematics 2016-02-16 R. Sharma , P. Devi , R. kumari

In this paper, we compute and verify the positivity of the Li coefficients for the Dirichlet $L$-functions using an arithmetic formula established in Omar and Mazhouda, J. Number Theory 125 (2007) no.1, 50-58; J. Number Theory 130 (2010)…

Number Theory · Mathematics 2015-07-14 Sami Omar , Raouf Ouni , Kamel Mazhouda

We establish a new version of the CR almost Schur Lemma which gives an estimation of the pseudohermitian scalar curvature on a compact strictly pseudoconvex pseudohermitian manifold to be a constant in terms of the norm of the traceless…

Differential Geometry · Mathematics 2022-04-08 Stefan Ivanov , Alexander Petkov

In this paper, we will give a horizontal gradient estimate of positive solutions of $\Delta_b u = - \lambda u$ on complete noncompact pseudo-Hermitian manifolds. As a consequence, we recapture the Liouville theorem of positive…

Differential Geometry · Mathematics 2018-02-23 Yibin Ren