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The new notion of adjoint algebraic entropy of endomorphisms of Abelian groups is introduced. Various examples and basic properties are provided. It is proved that the adjoint algebraic entropy of an endomorphism equals the algebraic…

Group Theory · Mathematics 2010-06-29 Dikran Dikranjan , Anna Giordano Bruno , Luigi Salce

In differential geometry, the existence of pullbacks is a delicate matter, since the category of smooth manifolds does not admit all of them. When pullbacks are required, often submersions are employed as an ideal class of maps which…

Category Theory · Mathematics 2025-03-03 Geoffrey Cruttwell , Marcello Lanfranchi

We introduce the critical Weinstein infinity-category -- the result of stabilizing the category of Weinstein sectors and inverting subcritical morphisms -- and for every finite collection P of integers, construct a P-flexibilization…

Symplectic Geometry · Mathematics 2025-12-05 Oleg Lazarev , Zachary Sylvan , Hiro Lee Tanaka

We show that for any amenable group \Gamma and any Z\Gamma-module M of type FL with vanishing Euler characteristic, the entropy of the natural \Gamma-action on the Pontryagin dual of M is equal to the L2-torsion of M. As a particular case,…

Dynamical Systems · Mathematics 2013-10-10 Hanfeng Li , Andreas Thom

We construct effective field theories for superconductors, that are powerful enough to describe low lying sub gap fermion modes localized to vortex cores, and at the same time resemble topological field theories in that there are no bulk…

Strongly Correlated Electrons · Physics 2014-05-23 Thors Hans Hansson , Thomas Kvorning , V. Parameswaran Nair

We say a completely positive contractive map between two C*-algebras has order zero, if it sends orthogonal elements to orthogonal elements. We prove a structure theorem for such maps. As a consequence, order zero maps are in one-to-one…

Operator Algebras · Mathematics 2009-03-20 Wilhelm Winter , Joachim Zacharias

By results of Rognerud, a source algebra equivalence between two $p$-blocks of finite groups induces an equivalence between the categories of cohomological Mackey functors associated with these blocks, and a splendid derived equivalence…

Group Theory · Mathematics 2015-10-07 Markus Linckelmann

Let $G$ be a simple algebraic group over an algebraically closed field $K$ of characteristic $p > 0$. We consider connected reductive subgroups $X$ of $G$ that contain a given distinguished unipotent element $u$ of $G$. A result of…

Group Theory · Mathematics 2020-01-20 Mikko Korhonen

By making use of the entropy function formalism we study the generalized attractor equations in the four dimensional N=2 supergravity in presence of higher order corrections. This result might be used to understand a possible ensemble one…

High Energy Physics - Theory · Physics 2009-11-11 Mohsen Alishahiha , Hajar Ebrahim

Working in the framework of Borel reducibility, we study various notions of embeddability between groups. We prove that the embeddability between countable groups, the topological embeddability between (discrete) Polish groups, and the…

Logic · Mathematics 2018-02-08 Filippo Calderoni , Luca Motto Ros

In the case of rational Cherednik algebras associated with cyclic groups, we give an alternative proof that the projective object $P_{\text{KZ}}$ representing the KZ-functor is isomorphic to the $\Delta$-module associated with the…

Representation Theory · Mathematics 2016-02-26 Sam Thelin

In the context of finite tensor products of Hilbert spaces, we prove that similarity of a tensor product of operator semigroups to a contraction semigroup is equivalent to the corresponding similarity for each factor, after an appropriate…

Functional Analysis · Mathematics 2025-09-04 J. Oliva-Maza , Y. Tomilov

We study self-similar groupoid actions on arbitrary directed graphs together with $\mathbb{T}$-valued twists that exhaust the second cohomology group of the associated Zappa-Sz\'ep product category. We define and analyse the associated…

Operator Algebras · Mathematics 2025-11-21 B. K. Kwaśniewski , A. Mundey

Basic properties of symplectic reflection algebras over an algebraically closed field k of positive characteristic are laid out. These algebras are always finite modules over their centres, in contrast to the situation in characteristic 0.…

Rings and Algebras · Mathematics 2007-09-17 Kenneth A. Brown , Kanokporn Changtong

We consider three (2-)categories and their (anti-)equivalence. They are the category of small abelian categories and exact functors, the category of definable additive categories and interpretation functors, the category of locally coherent…

Category Theory · Mathematics 2012-02-03 Mike Prest

Internal categories feature notions of limit and completeness, as originally proposed in the context of the effective topos. This paper sets out the theory of internal completeness in a general context, spelling out the details of the…

Category Theory · Mathematics 2020-04-21 Enrico Ghiorzi

We show that the zero locus of a normal function on a smooth complex algebraic variety S is algebraic provided that the normal function extends to a admissible normal function on a smooth compactification of S with torsion singularity. This…

Algebraic Geometry · Mathematics 2019-12-19 Patrick Brosnan , Gregory Pearlstein

The Pinsker subgroup of an abelian group with respect to an endomorphism was introduced in the context of algebraic entropy. Motivated by the nice properties and characterizations of the Pinsker subgroup, we generalize its construction in…

Group Theory · Mathematics 2011-03-01 Dikran Dikranjan , Anna Giordano Bruno

Consider a connected topological space $X$ with a point $x \in X$ and let $K$ be a field with the discrete topology. We study the Tannakian category of finite dimensional (flat) vector bundles on $X$ and its Tannakian dual $\pi_K (X,x)$…

Algebraic Topology · Mathematics 2023-07-04 Christopher Deninger

We introduce subshifts of quasi-finite type as a generalization of the well-known subshifts of finite type. This generalization is much less rigid and therefore contains the symbolic dynamics of many non-uniform systems, e.g., piecewise…

Dynamical Systems · Mathematics 2009-11-10 Jerome Buzzi