activity
20242026
collaborators

7 papers

math.AG2026

An axiomatization of six-functor formalisms

Josefien Kuijper

In this paper, we consider some variations on Mann's definition -categorical definition of abstract six-functor formalisms. We consider Nagata six-functor formalisms, that…

math.KT2025

Algebraic -theory for squares categories

Jonathan Campbell, Josefien Kuijper, Mona Merling +1

In this paper we introduce a new formalism for -theory, called squares -theory. This formalism allows us to simultaneously generalize the usual three-term relation $[B] = [A]…

math.KT2025

All K-theory is squares K-theory

Josefien Kuijper

We show that the K-theory spectra of many assemblers, such as the assembler of polytopes in euclidean, hyperbolic or spherical geometry, as well as the assembler of definable sets,…

math.KT2025

Higher Spherical Scissors Congruence I: Hopf Algebra

Inbar Klang, Josefien Kuijper, Cary Malkiewich +2

In the study of the generalization of Hilbert's Third Problem to spherical geometry, Sah constructed a Hopf algebra of spherical polytopes with product given by join and coproduct…

math.CT2025

From Hopf Algebras in Model Categories to Hopf Algebras in -categories

Inbar Klang, Josefien Kuijper, Cary Malkiewich +2

We show that algebra objects in model categories can be transferred to algebra objects in -categories, without any cofibrancy or fibrancy assumptions on the algebra. We fur…

math.AG2025

Uniqueness of six-functor formalisms

Adam Dauser, Josefien Kuijper

We present an alternative formulation of Scholze's notions of cohomologically proper and cohomologically étale with respect to an abstract six-functor formalism. These conditions…