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We introduce a contravariant functor, called Floer functor, from the category of Lagrangian conductors of a symplectic manifold to the homotopy category of bounded chain complexes of open strings in this manifold. The latter two categories…

Symplectic Geometry · Mathematics 2008-12-02 Jean-Yves Welschinger

We show that direct summands of certain additive functors arising as bifunctors with a fixed argument in an abelian category are again of that form whenever the fixed argument has finite length or, more generally, satisfies the descending…

Category Theory · Mathematics 2014-12-30 Alex Martsinkovsky

In terms of category theory, the Gromov homotopy principle for a set valued functor $F$ asserts that the functor $F$ can be induced from a homotopy functor. Similarly, we say that the bordism principle for an abelian group valued functor…

Algebraic Topology · Mathematics 2014-10-01 Rustam Sadykov

In this paper, we prove an equivariant version of the classical Dold-Thom theorem. Associated to a finite group, a CW-complex on which this group acts and a covariant coefficient system in the sense of Bredon, we functorially construct a…

Algebraic Topology · Mathematics 2007-08-01 Zhaohu Nie

We first give a short intrinsic, diagrammatic proof of the First Fundamental Theorem of invariant theory (FFT) for the special orthogonal group $\text{SO}_m(\mathbb{C})$, given the FFT for $\text{O}_m(\mathbb{C})$. We then define, by means…

Representation Theory · Mathematics 2016-12-14 Gustav Lehrer , Ruibin Zhang

Imprimitivity theorems provide a fundamental tool for studying the representation theory and structure of crossed-product C*-algebras. In this work, we show that the Imprimitivity Theorem for induced algebras, Green's Imprimitivity Theorem…

Operator Algebras · Mathematics 2007-05-23 Siegfried Echterhoff , S. Kaliszewski , John Quigg , Iain Raeburn

Motivated by problems in which data are given over covering generating families, we suggest a new cohomology theory for diffeological spaces, called diffeological \v{C}ech cohomology, which is an exact $ \partial $-functor of the section…

Differential Geometry · Mathematics 2023-03-07 Alireza Ahmadi

A multipath in a directed graph is a disjoint union of paths. The multipath complex of a directed graph ${\tt G}$ is the simplicial complex whose faces are the multipaths of ${\tt G}$. We compute the Euler characteristic, and associated…

Combinatorics · Mathematics 2022-08-10 Luigi Caputi , Carlo Collari , Sabino Di Trani , Jason P. Smith

The question of when the derived category of a ring satisfies Brown--Adams representability is revisited via studying the transfer of pure homological dimension along definable functors: it is shown that, for any ring, the pure global…

Representation Theory · Mathematics 2026-01-15 Isaac Bird

We introduce a new functor on categories of modular representations of reductive algebraic groups. Our functor has remarkable properties. For example it is a tensor functor and sends every standard and costandard object in the principal…

Representation Theory · Mathematics 2026-04-28 Joe Baine , Tasman Fell , Anna Romanov , Alexander Sherman , Geordie Williamson

If A is a nonnegative matrix whose associated directed graph is strongly connected, the Perron-Frobenius theorem asserts that A has an eigenvector in the positive cone, (R^+)^n. We associate a directed graph to any homogeneous, monotone…

Functional Analysis · Mathematics 2007-05-23 Stephane Gaubert , Jeremy Gunawardena

We prove that the category of directed graphs and graph maps carries a cofibration category structure in which the weak equivalences are the graph maps inducing isomorphisms on path homology.

Combinatorics · Mathematics 2025-12-23 Daniel Carranza , Brandon Doherty , Chris Kapulkin , Morgan Opie , Maru Sarazola , Liang Ze Wong

Directed Algebraic Topology is beginning to emerge from various applications. The basic structure we shall use for such a theory, a 'd-space', is a topological space equipped with a family of 'directed paths', closed under some operations.…

Algebraic Topology · Mathematics 2007-05-23 Marco Grandis

For each commutative, graded algebra with finite dimension in each degree, we construct a graded cohomology theory for graphs whose graded Euler characteristic is the chromatic polynomial of the graph. This extends our previous work which…

Quantum Algebra · Mathematics 2007-05-23 Laure Helme-Guizon , Yongwu Rong

Consider a complete abelian category which has an injective cogenerator. If its derived category is left--complete we show that the dual of this derived category satisfies Brown representability. In particular this is true for the derived…

Category Theory · Mathematics 2016-06-28 George Ciprian Modoi

Bivariant (equivariant) K-theory is the standard setting for non-commutative topology. We may carry over various techniques from homotopy theory and homological algebra to this setting. Here we do this for some basic notions from…

K-Theory and Homology · Mathematics 2015-10-23 Ralf Meyer , Ryszard Nest

Polynomial functors are sums of covariant representable functors from the category of sets to itself. They have a robust theory with many applications -- from operads and opetopes to combinatorial species. In this paper, we define a…

Category Theory · Mathematics 2020-04-10 David Jaz Myers , David I. Spivak

This paper brings together C*-algebras and algebraic topology in terms of viewing a C*-algebraic invariant in terms of a topological spectrum. E-theory, E(A,B), is a bivariant functor in the sense that is a cohomology functor in the first…

Operator Algebras · Mathematics 2017-08-11 Sarah L. Browne

Given a higher-rank graph $\Lambda$, we investigate the relationship between the cohomology of $\Lambda$ and the cohomology of the associated groupoid $G_\Lambda$. We define an exact functor between the abelian category of right modules…

Operator Algebras · Mathematics 2018-07-18 Elizabeth Gillaspy , Alexander Kumjian

An adjoint pair of contravariant functors between abelian categories can be extended to the adjoint pair of their derived functors in the associated derived categories. We describe the reflexive complexes and interpret the achieved results…

K-Theory and Homology · Mathematics 2009-05-20 Francesca Mantese , Alberto Tonolo