Results 91 to 100 of about 1,937 (197)

The Mathematical History Behind the Granger–Johansen Representation Theorem

Oxford Bulletin of Economics and Statistics, Volume 88, Issue 4, Page 587-602, August 2026.
ABSTRACT When can a vector time series that is integrated once (i.e., becomes stationary after taking first differences) be described in error correction form? The answer to this is provided by the Granger–Johansen representation theorem. From a mathematical point of view, the theorem can be viewed as essentially a statement concerning the geometry of ...
Johannes M. Schumacher
wiley   +1 more source

On Involutive Weak Exchange Algebras

Bulletin of the Section of Logic
In this paper, involutive weak exchange algebras (for short, involutive WE algebras) are introduced and studied. Their properties and characterizations are investigated. Some important results and examples are given.
Andrzej Walendziak
doaj   +1 more source

Finiteness of the Hölder–Brascamp–Lieb constant revisited

Bulletin of the London Mathematical Society, Volume 58, Issue 8, August 2026.
Abstract Abstract Hölder–Brascamp–Lieb inequalities have become a ubiquitous tool in Fourier analysis in recent years, due in large part to a theorem of Bennett et al. characterizing finiteness of the Hölder–Brascamp–Lieb constant. Here we provide a new characterization of a substantially different nature involving directed graphs of subspaces.
Philip T. Gressman
wiley   +1 more source

Another version of “exotic characterization of a commutative H∗-algebra”

International Journal of Mathematics and Mathematical Sciences, 2005
Commutative H∗-algebra is characterized in a somewhat unusual fashion without assuming either Hilbert space structure or commutativity. Existence of an involution is not postulated also.
Parfeny P. Saworotnow
doaj   +1 more source

Fine multidegrees, universal Gröbner bases, and matrix Schubert varieties

Journal of the London Mathematical Society, Volume 114, Issue 2, August 2026.
Abstract We give a criterion for a collection of polynomials to be a universal Gröbner basis for an ideal in terms of the multidegree of the closure of the corresponding affine variety in (P1)N$(\mathbb {P}^1)^N$. This criterion can be used to give simple proofs of several existing results on universal Gröbner bases.
Daoji Huang, Matt Larson
wiley   +1 more source

New elements in Hilbert algebras.

TFSS
In this paper‎, ‎the notion of commutator of elements of a Hilbert algebra are introduced and some properties are given‎. ‎The notions of involution element and Engel element in Hilbert algebras are introduced‎. ‎Many different characterizations of them are given‎.
openaire   +2 more sources

On Pták functions for bounded operators

Le Matematiche, 2014
The purpose of this paper is to prove that if the Pták function p is an operator norm, on \mathcal{B}(E), associated to a norm | . |, then (E, | . |) is a pseudo-Hilbert space.
Abdellah El Kinani
doaj  

Holographic observers for time-band algebras

Journal of High Energy Physics
We study the algebra of observables in a time band on the boundary of anti-de Sitter space in a theory of quantum gravity. Strictly speaking this algebra does not have a commutant because products of operators within the time band give rise to operators ...
Kristan Jensen, Suvrat Raju, Antony J. Speranza   +2 more
doaj   +1 more source

MULTIPLIERS IN HILBERT ALGEBRAS

Journal of the Chungcheong Mathematical Society, 2012
In this paper, we introduce the concept of multiplier in a Hilbert algebra and obtained some properties of multipliers. Also, we introduce the simple multiplier and characterized the kernel of multipliers in Hilbert algebras.
openaire   +1 more source

Hilbert Coefficients of Quadratic Algebras

Journal of Experimental Mathematics
If R = k[x1,...,xn]/I is a graded artinian algebra, then the length of k[x1,...,xn]/Is becomes a polynomial in s of degree n for large s. If we write this polynomial in the form ∑0<=i<=n (−1)i ei (s+n−i−1 choose n−i), then the ei's are called Hilbert coefficients of I.
openaire   +2 more sources