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Following our approach to metric Lie algebras developed in math.DG/0312243 we propose a way of understanding pseudo-Riemannian symmetric spaces which are not semi-simple. We introduce cohomology sets (called quadratic cohomology) associated…

Differential Geometry · Mathematics 2007-05-23 Ines Kath , Martin Olbrich

We introduce an approach to the categorification of rings, via the notion of distributive categories with negative objects, and use it to lay down categorical foundations for the study of super, quantum and non-commutative combinatorics.…

Category Theory · Mathematics 2009-05-27 Rafael Diaz , Eddy Pariguan

We propose and develop a new method to classify orbits of the spin group ${\rm Spin}(2d)$ in the space of its semi-spinors. The idea is to consider spinors as being built as a linear combination of their pure constituents, imposing the…

Combinatorics · Mathematics 2025-08-29 Niren Bhoja , Kirill Krasnov

We define a certain abstract planar algebra by generators and relations, study various aspects of its structure, and then identify it with Jones' spin planar algebra.

Operator Algebras · Mathematics 2019-02-01 Vijay Kodiyalam , Sohan Lal Saini , Sruthymurali , V. S. Sunder

The article consists of the Russian and English variants of Ph.D. Thesis in which the answers is given on the following questions: 1. how to construct the spinor formalism for n=6; 2. how to construct the spinor formalism for n=8; 3. how to…

Mathematical Physics · Physics 2012-04-03 K. V. Andreev

In this article, we determine the seven-dimensional almost Abelian Lie algebras which admit calibrated or parallel G_2-/G_2^*-structures. Along the way, we show that certain well-established curvature restrictions for calibrated and…

Differential Geometry · Mathematics 2013-07-23 Marco Freibert

In this note, we characterise the existence of non-trivial invariant spinors on maximal flag manifolds associated to complex simple Lie algebras. This characterisation is based on the combinatorial properties of their set of positive roots.…

Differential Geometry · Mathematics 2025-09-19 Diego Artacho , Uwe Semmelmann

The twined almost commutative structure of the standard spectral triple on the noncommutative torus with rational parameter is exhibited, by showing isomorphisms with a spectral triple on the algebra of sections of certain bundle of…

Quantum Algebra · Mathematics 2019-06-26 Alessandro Carotenuto , Ludwik Dabrowski

We establish a twistor correspondence between a cuspidal cubic curve in a complex projective plane, and a co-calibrated homogeneous $G_2$ structure on the seven--dimensional parameter space of such cubics. Imposing the Riemannian reality…

Differential Geometry · Mathematics 2012-01-27 Boris Doubrov , Maciej Dunajski

This work gives a classification of imprimitive irreducible finite subgroups of the orthogonal group O(7) plus the number of conjugate classes for each group.

Group Theory · Mathematics 2016-08-29 David B. Wales

We investigate spin as algebraic structure within the q-deformed Poincare algebra, proceeding in the same manner as in the undeformed case. The q-Pauli-Lubanski vector, the q-spin Casimir, and the q-little algebras for the massless and the…

Quantum Algebra · Mathematics 2007-05-23 Christian Blohmann

We show that all spin groups of non-definite, quinary quadratic forms over a field with characteristic 0 can be represented as 2 by 2 matrices with entries in an associated quaternion algebra. Over local and global fields, we further study…

Number Theory · Mathematics 2019-09-30 Arseniy Sheydvasser

We investigate the seven sphere as a soft Lie algebra i.e. an algebra with structure functions instead of structure constants. We calculate its structure functions explicitly and also discuss some relevant points such as the validity of the…

Mathematical Physics · Physics 2007-05-23 Khaled Abdel-Khalek

We present a systematic study of symmetries, invariants and moduli spaces of classes of coframes. We introduce a classifying Lie algebroid to give a complete description of the solution to Cartan's realization problem that applies to both…

Differential Geometry · Mathematics 2012-10-08 Rui Loja Fernandes , Ivan Struchiner

In the present text we discuss basic aspects of the Seiberg - Witten theory mainly focusing the attantion on some geometrical details which could make the introduction to the subject more illustrative. At the same time we list there natural…

Differential Geometry · Mathematics 2007-05-23 Nik. Tyurin

The paper concerns the classification problem of a subclass of complex filiform Leibniz algebras in dimensions 7 and 8. This subclass arises from naturally graded filiform Lie algebras. We give a complete list of isomorphism classes of…

Rings and Algebras · Mathematics 2010-04-19 Isamiddin S. Rakhimov , Munther A. Hassan

We study closed, connected, spin 4-manifolds up to stabilisation by connected sums with copies of $S^2 \times S^2$. For a fixed fundamental group, there are primary, secondary and tertiary obstructions, which together with the signature…

Geometric Topology · Mathematics 2024-06-07 Daniel Kasprowski , Mark Powell , Peter Teichner

In this paper we consider the algebraic structures related to invariants of topological structures introduced respectively in [CEKL22] and [ADEM19]. Our main results is to show how all these structures are closely related to each other…

Group Theory · Mathematics 2023-11-27 Marco Bonatto

In this paper, which is a complement of \cite{BG}, we study a few elementary invariants for configurations of skew lines, as introduced and analyzed first by Viro and his collaborators. We slightly simplify the exposition of some known…

Combinatorics · Mathematics 2010-06-18 Roland Bacher , David Garber

It is shown that the compact Lie group SU(3) admits an Sp(2)Sp(1)-structure whose distinguished 2-forms $\omega_1,\omega_2,\omega_3$ span a differential ideal. This is achieved by first reducing the structure further to a subgroup…

Differential Geometry · Mathematics 2010-04-02 Oscar Macia