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Related papers: The Calkin algebra has outer automorphisms

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We consider various quotients of the C*-algebra of bounded operators on a nonseparable Hilbert space, and prove in some cases that, consistently, there are many outer automorphisms.

Logic · Mathematics 2013-03-20 Ilijas Farah , Paul McKenney , Ernest Schimmerling

We prove that it is relatively consistent with the usual axioms of mathematics that all automorphisms of the Calkin algebra are inner. Together with a 2006 Phillips--Weaver construction of an outer automorphism using the Continuum…

Operator Algebras · Mathematics 2010-05-25 Ilijas Farah

In 2007 Phillips and Weaver showed that, assuming the Continuum Hypothesis, there exists an outer automorphism of the Calkin algebra. (The Calkin algebra is the algebra of bounded operators on a separable complex Hilbert space, modulo the…

Operator Algebras · Mathematics 2019-08-16 Samuel Coskey , Ilijas Farah

Two automorphisms of a simple stable AF algebra with a finite dimensional lattice of lower semicontinuous traces are shown to be outer conjugate if they act in the same way on the K-group and the extremal traces are scaled by numbers which…

Operator Algebras · Mathematics 2007-05-23 Ola Bratteli , Akitaka Kishimoto

The question of existence of outer automorphisms of a simple algebraic group $G$ arises naturally both when working with the Galois cohomology of $G$ and as an example of the algebro-geometric problem of determining which connected…

Group Theory · Mathematics 2016-09-14 Skip Garibaldi , Holger P. Petersson

We prove that the statement `For all Borel ideals I and J on $\omega$, every isomorphism between Boolean algebras $P(\omega)/I$ and $P(\omega)/J$ has a continuous representation' is relatively consistent with ZFC. In this model every…

Logic · Mathematics 2012-11-16 Ilijas Farah , Saharon Shelah

In functional analysis, approximative properties of an object become precise in its ultrapower. We discuss this idea and its consequences for automorphisms of II_1 factors. Here are some sample results: (1) an automorphism is approximately…

Operator Algebras · Mathematics 2008-09-26 David Sherman

In this note, we compute the group of automorphisms of Projective, Affine and Euclidean Geometries in the sense of Klein. As an application, we give a simple construction of the outer automorphism of S_6.

Group Theory · Mathematics 2013-07-05 Alberto Navarro , Jose Navarro

The groups of automorphisms of the Jacobian algebras are found.

Algebraic Geometry · Mathematics 2011-09-13 V. V. Bavula

The Proper Forcing Axiom implies all automorphisms of every Calkin algebra associated with an infinite-dimensional complex Hilbert space and the ideal of compact operators are inner. As a means of the proof we introduce the notion of Polish…

Logic · Mathematics 2011-03-18 Ilijas Farah

Let $q$ be an algebraic Lie algebra and $q<m>$ a (generalised) Takiff algebra. Any finite order automorphism $\theta$ of $q$ induces an automorphisms of $q<m>$ of the same order, denoted $\Theta$. We study invariant-theoretic properties of…

Representation Theory · Mathematics 2007-10-12 Dmitri I. Panyushev

We prove that every $2$-local automorphism on a finite-dimensional semi-simple Lie algebra $\mathcal{L}$ over an algebraically closed field of characteristic zero is an automorphism. We also show that each finite-dimensional nilpotent Lie…

Rings and Algebras · Mathematics 2016-02-18 Shavkat Ayupov , Karimbergen Kudaybergenov

We give elementary proofs of the following two theorems on automorphisms of a finite group G: (1) An automorphism of G is inner if and only if it extends to an automorphism of every finite group containing G. (2) There exists a finite…

Group Theory · Mathematics 2024-05-07 Benjamin Sambale

We show that, for each finite algebra A, either it has symmetric term operations of all arities or else some finite algebra in the variety generated by A has two automorphisms without a common fixed point. We also show this two-automorphism…

Rings and Algebras · Mathematics 2016-05-16 Catarina Carvalho , Andrei Krokhin

We discuss the existence of (injectively) universal C*-algebras and prove that all C*-algebras of density character $\aleph_1$ embed into the Calkin algebra, $Q(H)$. Together with other results, this shows that each of the following…

Operator Algebras · Mathematics 2018-10-17 Ilijas Farah , Ilan Hirshberg , Alessandro Vignati

We describe the groups of automorphisms of two generated free braided associative algebras with involutive diagonal braidings over a field of characteristic $\neq 2$. Depending on the form of the diagonal involutive braiding, five different…

Rings and Algebras · Mathematics 2021-03-12 Riza Mutalip , Altyngul Naurazbekova , Ualbai Umirbaev

The present paper is devoted to the description of local and 2-local automorphisms on Cayley algebras over an arbitrary field $\mathbb{F}$. Given a Cayley algebra $\mathcal{C}$ with norm $n$, let $O(\mathcal{C},n)$ be the corresponding…

Rings and Algebras · Mathematics 2021-07-05 Shavkat Ayupov , Alberto Elduque , Karimbergen Kudaybergenov

The automorphisms groups and derivation algebras of all two-dimensional algebras over algebraically closed fields are described.

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

We describe the outer automorphism group of a one-ended fundamental group of a graph of groups, when edge groups are cyclic, and vertex groups are torsion-free with cyclic centralizers. We show that in this case the outer automorphism group…

Group Theory · Mathematics 2025-07-23 Dario Ascari , Montserrat Casals-Ruiz , Ilya Kazachkov

In this paper we prove that over algebraically closed field $K$ of positive characteristic $\neq 2$ every automorphism of the group of origin-preserving automorphisms of the polynomial algebra $K[x_1,\ldots, x_n]$ ($n>3$) which fixes every…

Algebraic Geometry · Mathematics 2021-03-25 Alexei Belov-Kanel , Andrey Elishev , Jie-Tai Yu
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