Locally constant functors

拓扑中的六运算

The six operations in topology

本文将局部紧Hausdorff空间上的层六函子形式体系推广至取值于稳定双完备闭对称幺半∞-范畴的层，研究局部可缩几何态射的性质，并给出Atiyah对偶的六函子表述。

通过六函子形式体系的同调流形

Homology manifolds via six functor formalisms

利用谱层六函子形式体系研究同调流形，刻画上同调光滑对象，证明ANR同调流形是Poincaré对偶复形，推广Wilder单调映射定理，引入同伦流形并证明不稳定版本的Wilder可定向猜想。

On the proper homotopy type of locally compact A^2_n-polyhedra

In this paper we address the classification problem for locally compact (n-1)-connected CW-complexes with dimension less or equal than n+2 up to proper homotopy type. We obtain complete classification theorems in terms of purely algebraic data in those cases where the representation type of the involved algebra is finite. For this we define new quadratic functors in controlled algebra and new homotopy and cohomology invariants in proper homotopy theory.

Some remarks on Mackey functors

The purpose of this paper is mainly to record how certain homotopy-theoretical constructions on ordinary G-equivariant cohomology spectra HM for a Mackey functor M, in particular products and duality, can be described on chain level. We will also discuss certain facts about modules over the constant Green functor $\underline{\mathbb{Z}}$.

The homotopy-invariance of constructible sheaves

The purpose of this paper is to explain why the functor that sends a stratified topological space $S$ to the $\infty$-category of constructible (hyper)sheaves on $S$ with coefficients in a large class of presentable $\infty$categories is homotopy-invariant. To do this, we first establish a number of results in the unstratified setting, i.e., the setting of locally constant (hyper)sheaves. For example, if $X$ is a locally weakly contractible topological space and $\mathcal{E}$ is a presentable $\infty$-category, then we give a concrete formula for the constant hypersheaf functor $\mathcal{E}\to…

Foncteurs de division et structure de I tenseur 2 tenseur Lambda n dans la catégorie F

We prove that, in the category F of functors between F\_2-vector spaces, the tensor product between the second non constant standard injective functor and an exterior power functor is artinian. The only cas known to date was the artinian character of this injective ; our result is a step in the study of the third non constant standard injective. We use the division functor by the identity functor and facts from modular representation theory of the symmetric groups to obtain this theorem by detecing suitable composition factors.

Recovering a cohomological Mackey Functor from its restriction to Sylow subgroups

We explain how to recover the top level of a cohomological G-Mackey functor $\underline{M}$ from the restriction of $\underline{M}$ to each of the Sylow subgroups of G. As an application, we compute the Mackey functor valued G-equivariant homology groups of a point with constant $\mathbb{Z}$-coefficients when G has order pq for odd primes p<q. We also indicate how the calculation goes for $G=A_4$.

A convenient category of locally preordered spaces

As a practical foundation for a homotopy theory of abstract spacetime, we extend a category of certain compact partially ordered spaces to a convenient category of locally preordered spaces. In particular, we show that our new category is Cartesian closed and that the forgetful functor to the category of compactly generated spaces creates all limits and colimits.

Exponential growth of homotopy groups of suspended finite complexes

We study the asymptotic behavior of the homotopy groups of simply connected finite $p$-local complexes, and define a space to be locally hyperbolic if its homotopy groups have exponential growth. Under some certain conditions related to the functorial decomposition of loop suspension, we prove that the suspended finite complexes are locally hyperbolic if suitable but accessible information of the homotopy groups is known. In particular, we prove that Moore spaces are locally hyperbolic, and other candidates are also given.

Parametrized spaces model locally constant homotopy sheaves

We prove that the homotopy theory of parametrized spaces embeds fully and faithfully in the homotopy theory of simplicial presheaves, and that its essential image consists of the locally homotopically constant objects. This gives a homotopy-theoretic version of the classical identification of covering spaces with locally constant sheaves. We also prove a new version of the classical result that spaces parametrized over X are equivalent to spaces with an action of the loop space of X. This gives a homotopy-theoretic version of the correspondence between covering spaces over X and sets with an a…

一点的 $RO(D_{2p})$-分次上同调的 Green 函子结构

The Green functor structure of $RO(D_{2p})$-graded cohomology of a point

本文计算了常系数下一点的 $RO(D_{2p})$-分次上同调及其 Green 函子结构，推广了 Kriz-Lu 的加性计算结果。

$E$-theory of $X$-$C^{*}$-algebras and functor formalisms

$E$-theory of $X$-$C^{*}$-algebras and functor formalisms

本文研究了局部紧 Hausdorff 空间上的 $E$-理论作为六 functor 形式化，并证明其等价于 $E$-valued sheaves 的六 functor 形式化，同时展示了可表示为有限开子 locale 联合的 locale 的 $E$-理论范畴等价于 $E$-valued cosheaves 的范畴。