English
Related papers

Related papers: Complex and real ranks of reducible cubics

200 papers

We study rationality properties of real singular cubic threefolds.

Algebraic Geometry · Mathematics 2024-11-22 Ivan Cheltsov , Yuri Tschinkel , Zhijia Zhang

It is well-known that every commutative separable unital C*-algebra of real rank zero is a quotient of the C*-algebra of all compex continous functions defined on the Cantor cube. We prove a non-commutative version of this result by showing…

Operator Algebras · Mathematics 2007-05-23 Alex Chigogidze

We use floor decompositions of tropical curves to prove that any enumerative problem concerning conics passing through projective-linear subspaces in $\RP^n$ is maximal. That is, there exist generic configurations of real linear spaces such…

Algebraic Geometry · Mathematics 2011-02-10 Erwan Brugallé , Nicolas Puignau

We introduce the decomposition rank, a notion of covering dimension for nuclear C^*-algebras. The decomposition rank generalizes ordinary covering dimension and has nice permanence properties; in particular, it behaves well with respect to…

Operator Algebras · Mathematics 2007-05-23 Eberhard Kirchberg , Wilhelm Winter

A complete classification and character formulas for finite-dimensional irreducible representations of the rational Cherednik algebra of type A is given. Less complete results for other types are obtained. Links to the geometry of affine…

Representation Theory · Mathematics 2007-05-23 Yuri Berest , Pavel Etingof , Victor Ginzburg

We classify all conformal irreducible modules of finite type over the Cheng Kac superalgebra CK(6).

Representation Theory · Mathematics 2012-04-04 Consuelo Martínez , Efim Zelmanov

We present all real solvable algebraically rigid Lie algebras of dimension $n\leq 8$. The difference between the classification of complex and real rigid Lie algebras is analyzed.

Representation Theory · Mathematics 2007-05-23 J. M. Ancochea bermudez , R. Campoamor-Stursberg , M. Goze , L. Garcia Vergnolle

In this paper, we give a complete classification of irreducible bounded weight modules over the derivation Lie algebras of rational quantum tori

Representation Theory · Mathematics 2020-01-10 Genqiang Liu , Kaiming Zhao

We explore various limit constructions for C*-algebras, such as composition series and inverse limits, in relation to the notions of real rank, stable rank, and extremal richness. We also consider extensions and pullbacks. We identify some…

Operator Algebras · Mathematics 2017-06-09 Lawrence G. Brown , Gert K. Pedersen

In this paper we develop the formalism of rational complex Bezier curves. This framework is a simple extension of the CAD paradigm, since it describes arc of curves in terms of control polygons and weights, which are extended to complex…

Numerical Analysis · Mathematics 2025-12-10 A. Canton , L. Fernandez-Jambrina , M. J. Vazquez-Gallo

We introduce the notion of ''maximal rank type'' for representations of quivers, which requires certain collections of maps involved in the representation to be of maximal rank. We show that real root representations of quivers are of…

Representation Theory · Mathematics 2008-07-14 Marcel Wiedemann

We introduce a notion of real rank zero for inclusions of C$^*$-algebras. After showing that our definition has many equivalent characterisations, we offer a complete description of the commutative case. We provide permanence and…

Operator Algebras · Mathematics 2025-09-03 James Gabe , Robert Neagu

We analyze the problem of determining Waring decompositions of the powers of any quadratic form over the field of complex numbers. Our main goal is to provide information about their rank and also to obtain decompositions whose size is as…

Algebraic Geometry · Mathematics 2025-04-22 Cosimo Flavi

A polynomial transformation of the real plane $\Bbb R^2$ is a mapping $\Bbb R^2\to\Bbb R^2$ given by two polynomials of two variables. Such a transformation is called cubic if the degrees of its polynomials are not greater than three. In…

Algebraic Geometry · Mathematics 2015-08-20 Ruslan Sharipov

We show that if $K$ is a monogenic, primitive, totally real number field, that contains units of every signature, then there exists a lower bound for the rank of integer universal quadratic forms defined over $K$. In particular, we extend…

Number Theory · Mathematics 2018-08-07 Pavlo Yatsyna

We obtain a computable structure of Scott rank omega_1^{CK} (call this ock), and give a general coding procedure that transforms any hyperarithmetical structure A into a computable structure A' such that the rank of A is ock, ock+1, or <…

Logic · Mathematics 2007-05-23 Julia Knight , Jessica Millar

We study the space of real rational curves of low degree in the quadric of signature $(3,2)$ and provides a classificaton of real rational knots and nodal curves. Apart from the classification, we also study the relationship between the…

Geometric Topology · Mathematics 2026-03-30 Shane D'Mello , Priya Rani

We highlight some facts about continued fractions of real cubic irrationalities. This may be thought as a small section in a textbook on continued fractions.

Number Theory · Mathematics 2023-11-29 Wadim Zudilin

We investigate properties of Waring decompositions of real homogeneous forms. We study the moduli of real decompositions, so-called Space of Sums of Powers, naturally included in the Variety of Sums of Powers. Explicit results are obtained…

Algebraic Geometry · Mathematics 2016-12-26 Mateusz Michałek , Hyunsuk Moon

We describe some forms with greater Waring rank than previous examples. In $3$ variables we give forms of odd degree with strictly greater rank than the ranks of monomials, the previously highest known rank. This narrows the possible range…

Algebraic Geometry · Mathematics 2015-08-07 Jarosław Buczyński , Zach Teitler