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The rational fixed point of a set functor is well-known to capture the behaviour of finite coalgebras. In this paper we consider functors on algebraic categories. For them the rational fixed point may no longer be fully abstract, i.e. a…

Logic in Computer Science · Computer Science 2023-06-22 Stefan Milius

We calculate the rational representation-ring-graded stable stems for rank 1 groups, SU(2), SO(3), Pin (2), O(2), Spin(2) and SO(2), in the same spirit as the calculations for finite groups in arXiv:2205.02382 with J.D.Quigley. This…

Algebraic Topology · Mathematics 2026-01-16 J. P. C. Greenlees

We study some basic properties of schematic homotopy types and the schematization functor. We describe two different algebraic models for schematic homotopy types: co-simplicial Hopf alegbras and equivariant co-simplicial algebras, and…

Algebraic Geometry · Mathematics 2014-01-14 L. Katzarkov , T. Pantev , B. Toen

The paper deals with a construction of a separating system of rational invariants for finite dimensional generic algebras. In the process of dealing an approach to a rough classification of finite dimensional algebras is offered by…

Rings and Algebras · Mathematics 2018-01-17 U. Bekbaev

By a theorem of Suslin, a Tor-unital (not necessarily unital) ring satisfies excision in algebraic K-theory. We give a new and direct proof of Suslin's result based on an exact sequence of categories of perfect modules. In fact, we prove a…

K-Theory and Homology · Mathematics 2019-02-20 Georg Tamme

Consider a coring with exact rational functor, and a finitely generated and projective right comodule. We construct a functor (\emph{coinduction functor}) which is right adjoint to the hom-functor represented by this comodule. Using the…

Rings and Algebras · Mathematics 2009-02-13 L. El Kaoutit , J. Gómez-Torrecillas

The equations for the electromagnetic field in an anisotropic media are written in a form containing only the transverse field components relative to a half plane boundary. The operator corresponding to this formulation is the…

Mathematical Physics · Physics 2009-08-11 B. L. G. Jonsson

This paper supplies additions to our paper in Linear Algebra Appl. 510 (2016) 395--420 on integral spans of tight frames in Euclidean spaces. In that previous paper, we considered the case of an equiangular tight frame (ETF), proving that…

Number Theory · Mathematics 2018-10-15 Albrecht Boettcher , Lenny Fukshansky

We study some subsets of rational points in an algebraic groups defined by open conditions on their projection in the finite adeles points. Using adelic mixing we are able to prove an equidistribution's result for the projection of these…

Number Theory · Mathematics 2007-09-18 Antonin Guilloux

We consider a flat lattice of dipoles modeled by harmonic oscillators interacting with the electromagnetic field in dipole approximation. Eliminating the variables from the coupled equations of motion, we come to effective Maxwell…

Quantum Physics · Physics 2015-06-19 M. Bordag

Reflexive functors of modules naturally appear in Algebraic Geometry, mainly in the theory of linear representations of group schemes, and in "duality theories". In this paper we study and determine reflexive functors and we give many…

Commutative Algebra · Mathematics 2013-10-23 J. Navarro , C. Sancho , P. Sancho

We prove that rational and 1-rational singularities of complex spaces are stable under taking quotients by holomorphic actions of reductive and compact Lie groups. This extends a result of Boutot to the analytic category and yields a…

Complex Variables · Mathematics 2015-04-17 Daniel Greb

We show the vanishing of the second homotopy group of the \'etale homotopy type of a smooth connected algebraic group over a separably closed field, completed away from the characteristic. This is an algebraic analogue of a classical…

Algebraic Geometry · Mathematics 2022-06-23 Cyril Demarche , Tamás Szamuely

The satellite endofunctors are used to extend the definition of linkage of ideals to the linkage of totally finitely presented functors. The new notion for linkage works over a larger class of rings and is consistent with the functorial…

Representation Theory · Mathematics 2015-10-14 Jeremy Russell

We improve the decoupling exponent for functions with spectrum inside AD-regular collections of arcs on the parabola. We achieve this by incorporating recent Szemer\'{e}di--Trotter-type estimates into the bootstrapping argument from…

Classical Analysis and ODEs · Mathematics 2026-05-26 Ciprian Demeter , Yuqiu Fu

We consider a conjectured topological inequality for the number of equisingular moduli of a rational surface singularity, and prove it in some natural special cases. When the resolution dual graph is "sufficiently negative" (in a precise…

Algebraic Geometry · Mathematics 2016-03-28 Jonathan Wahl

We construct a rational extension of a recently studied nonlinear quantum oscillator model. Our extended model is shown to retain exact solvability, admitting a discrete spectrum and corresponding closed-form solutions that are expressed…

Mathematical Physics · Physics 2015-06-18 Axel Schulze-Halberg , Barnana Roy

In this note, we address the following question: Why certain nonassociative algebra structures emerge in the regularity theory of elliptic type PDEs and also in constructing nonclassical and singular solutions? The aim of the paper is…

Analysis of PDEs · Mathematics 2021-02-12 Vladimir G. Tkachev

In this paper we show that a split central simple algebra with quadratic pair which decomposes into a tensor product of quaternion algebras with involution and a quaternion algebra with quadratic pair is adjoint to a quadratic Pfister form.…

Rings and Algebras · Mathematics 2016-04-15 Karim Johannes Becher , Andrew Dolphin

Following Zagier, this work studies the rationality and divisibility of Fourier coefficients of meromorphic Hilbert modular forms associated with real quadratic fields, using theta lifts and weak Maass forms. We establish conditions where…

Number Theory · Mathematics 2024-11-04 Baptiste Depouilly