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We confirm, to some extent, the belief that a projective variety X has the largest number (relative to the dimension of X) of independent commuting automorphisms of positive entropy only when X is birational to a complex torus or a quotient…

Algebraic Geometry · Mathematics 2018-09-24 De-Qi Zhang

In this text we signal a serious gap in the proof of the main theorem of our paper and explain which parts of the statement remain valid. In fact, the main theorem remains valid unless possibly the variety does not admit…

Algebraic Geometry · Mathematics 2023-04-21 Frédéric Campana , Andreas Höring , Thomas Peternell

To follow up on the results of [1], we propose a computationally efficient explicit cyclic decomposition of the maximal tori in the groups $SL_n(q)$ and $SU_n(q)$ and their projective images. We also derive some corollaries to simplify…

Group Theory · Mathematics 2019-08-08 Andrei V. Zavarnitsine

We construct a projective variety with discrete, non-finitely generated automorphism group. As an application, we show that there exists a complex projective variety with infinitely many non-isomorphic real forms.

Algebraic Geometry · Mathematics 2017-02-08 John Lesieutre

We consider linear groups which do not contain unipotent elements of infinite order, which includes all linear groups in positive characteristic, and show that this class of groups has good properties which resemble those held by groups of…

Group Theory · Mathematics 2018-11-04 J. O. Button

We prove a flat torus theorem for quadric complexes. In particular, we show that if a non-cyclic free abelian group $G$ acts metrically properly on a quadric complex $X$, then $G \cong \mathbb{Z}^2$ and $X$ contains a $G$-invariant…

Group Theory · Mathematics 2026-05-22 Nima Hoda , Zachary Munro

Let $X$ be a partially ordered set, $R$ a commutative $2$-torsionfree unital ring and $FI(X,R)$ the finitary incidence algebra of $X$ over $R$. In this note we prove that each $R$-linear Jordan isomorphism of $FI(X,R)$ onto an $R$-algebra…

Rings and Algebras · Mathematics 2017-03-08 Rosali Brusamarello , Érica Z. Fornaroli , Mykola Khrypchenko

We classify two classes of B_2-graded Lie algebras which have a second compatible grading by an abelian group A: (a) graded-simple Lie algebras for A torsion-free and (b) division-A-graded Lie algebras. Our results describe the centreless…

Rings and Algebras · Mathematics 2013-12-17 Erhard Neher , Maribel Tocón

Let $V$ be a finite dimensional complex linear space and let $G$ be an irreducible finite subgroup of $\GL(V)$. For a $G$-invariant lattice $\Lambda$ in $V$ of maximal rank, we give a description of structure of the complex torus…

Algebraic Geometry · Mathematics 2007-05-23 Vladimir L. Popov , Yuri G. Zarhin

We prove a Berger type theorem for the normal holonomy group (i.e., the holonomy group of the normal connection) of a full complete complex submanifold of the complex projective space. Namely, if the normal holonomy does not act…

Differential Geometry · Mathematics 2008-08-20 Sergio Console , Antonio J. Di Scala , Carlos Olmos

We classify finite groups acting by birational transformations of a non-trivial Severi--Brauer surface over a field of characteristc zero that are not conjugate to subgroups of the automorphism group. Also, we show that the automorphism…

Algebraic Geometry · Mathematics 2020-07-02 Constantin Shramov

The Resolution Theorem for Compact Abelian Groups is applied to show that the profinite subgroups of a finite-dimensional compact connected abelian group (protorus) which induce tori quotients comprise a lattice under intersection (meet)…

Group Theory · Mathematics 2025-03-28 Wayne Lewis

We investigate surjective isometries between projection lattices of two von Neumann algebras. We show that such a mapping is characterized by means of Jordan $^*$-isomorphisms. In particular, we prove that two von Neumann algebras without…

Operator Algebras · Mathematics 2018-10-23 Michiya Mori

A complete classifications of two-dimensional general, commutative, commutative Jordan, division and evolution real algebras are given. In the case of evolution algebras their groups of automorphisms and derivation algebras are described as…

Rings and Algebras · Mathematics 2018-12-04 U. Bekbaev

The classification, up to isomorphism, of two-dimensional (not necessarily commutative) Jordan algebras over algebraically closed fields and $\mathbb{R}$ is presented in terms of their matrices of structure constants.

Rings and Algebras · Mathematics 2018-12-10 H. Ahmed , U. Bekbaev , I. Rakhimov

In this paper, we prove that the Jordan-Kinderlehrer-Otto scheme for a family of linear parabolic equations on the flat torus converges uniformly in space.

Analysis of PDEs · Mathematics 2015-10-12 Paul W. Y. Lee

We prove a Jordan decomposition theorem for minimal connected simple groups of finite Morley rank with non-trivial Weyl group. From this, we deduce a precise structural description of Borel subgroups of this family of simple groups. Along…

Logic · Mathematics 2010-09-17 Tuna Altinel , Jeffrey Burdges , Oliver Frecon

A theorem of Picard's type is proved for entire holomorphic mappings into complex projective varieties. This theorem has local character in the sense that the existence of Julia directions can be proved under a natural additional…

Complex Variables · Mathematics 2025-07-30 Alexandre Eremenko

\'{E}tale difference algebraic groups are a difference analog of \'{e}tale algebraic groups. Our main result is a Jordan-H\"{o}lder type decomposition theorem for these groups. Roughly speaking, it shows that any \'{e}tale difference…

Algebraic Geometry · Mathematics 2021-08-11 Michael Wibmer

Let T be be a zero-product preserving bounded linear map between C*-algebras A and B. Here neither A nor B is necessarily unital. In this note, we investigate when T gives rise to a Jordan homomorphism. In particular, we show that A and B…

Operator Algebras · Mathematics 2007-08-29 Ngai-Ching Wong