activity
20172026
most citedHomotopy (Pre-)Derivators of Cofibration Categories and Quasi-Categories

6 citations · 16 across the 19 of their papers we have counts for

collaborators

21 papers

math.AT2026

Global -categories and global Thom spectra

Emma Brink, Tobias Lenz

We introduce a framework of (Lie-)global -categories, which formalizes various families of -categories indexed by compact Lie groups and equipped with suitable rest…

math.AT2025

Mackey functors and classical equivariant -theory

Tobias Lenz

We show that the spectral Mackey functors associated to the equivariant algebraic -theory spectra of Guillou-May and Merling (originally constructed using pointset models) can b…

math.CT2025

Revisiting -naturality of the Yoneda embedding

Tobias Lenz

We show that the Yoneda embedding 'is' -natural with respect to the functoriality of presheaves via left Kan extension, refining the -categorical result pro…

math.CT2025

Universality of span 2-categories and the construction of 6-functor formalisms

Bastiaan Cnossen, Tobias Lenz, Sil Linskens

Given an -category equipped with suitable wide subcategories , we show that the -category $\text{S}{\scriptstyle\text{PAN}}_2(C,E)_…

math.AT2025

Norms in equivariant homotopy theory

Tobias Lenz, Sil Linskens, Phil Pützstück

We show that the -category of normed algebras in genuine -spectra, as introduced by Bachmann-Hoyois, is modelled by strictly commutative algebras in -symmetric spectr…

math.AT2025★ 1 cited

Universality of Barwick's unfurling construction

Bastiaan Cnossen, Tobias Lenz, Maxime Ramzi

Given an -category with pullbacks, its -category of spans has the universal property of freely adding right adjoints…

math.AT2024

Normed equivariant ring spectra and higher Tambara functors

Bastiaan Cnossen, Rune Haugseng, Tobias Lenz +1

In this paper we extend equivariant infinite loop space theory to take into account multiplicative norms: For every finite group , we construct a multiplicative refinement of th…

math.AT2024

Parametrized (higher) semiadditivity and the universality of spans

Bastiaan Cnossen, Tobias Lenz, Sil Linskens

Semiadditivity of an -category, i.e. the existence of biproducts, provides it with useful algebraic structure in the form of a canonical enrichment in commutative monoids.…

math.CT2024

Homotopical commutative rings and bispans

Bastiaan Cnossen, Rune Haugseng, Tobias Lenz +1

We prove that commutative semirings in a cartesian closed presentable -category, as defined by Groth, Gepner, and Nikolaus, are equivalent to product-preserving functors fr…

math.AT2023

The Adams isomorphism revisited

Bastiaan Cnossen, Tobias Lenz, Sil Linskens

We establish abstract Adams isomorphisms in an arbitrary equivariantly presentable equivariantly semiadditive global category. This encompasses the well-known Adams isomorphism in…

math.AT2023

Simplicial -modules and mild actions

Tobias Lenz, Anna Marie Schröter

We develop an analogue of the theory of -modules in the world of simplicial sets, based on actions of a certain simplicial monoid originally appearing in the const…

math.AT2023

Partial parametrized presentability and the universal property of equivariant spectra

Bastiaan Cnossen, Tobias Lenz, Sil Linskens

We introduce a notion of partial presentability in parametrized higher category theory and investigate its interaction with the concepts of parametrized semiadditivity and stabilit…

math.AT2023

Global model categories and topological André-Quillen cohomology

Tobias Lenz, Michael Stahlhauer

We introduce global model categories as a general framework to capture several phenomena in global equivariant homotopy theory. We then construct genuine stabilizations of these, g…

math.AT2023★ 1 cited

Parametrized stability and the universal property of global spectra

Bastiaan Cnossen, Tobias Lenz, Sil Linskens

We develop a framework of parametrized semiadditivity and stability with respect to so-called atomic orbital subcategories of an indexing -category , extending work of N…

math.AT2022★ 2 cited

Genuine vs. naïve symmetric monoidal G-categories

Tobias Lenz

We prove that through the eyes of equivariant weak equivalences the genuine symmetric monoidal -categories of Guillou and May [Algebr. Geom. Topol. 17 (2017), no. 6, 3259-3339;…

math.AT2022

Global homotopy theory via spectral Mackey functors

Tobias Lenz

We show that Hausmann's model of global stable homotopy theory in terms of symmetric spectra is equivalent to the -category of spectral Mackey functors in the sense of Barw…

math.AT2021

Categorical models of unstable G-global homotopy theory

Tobias Lenz

We prove that the category of small categories with -action forms a model of unstable -global homotopy theory for every discrete group , generalizing Schw…

math.AT2020★ 3 cited

G-Global Homotopy Theory and Algebraic K-Theory

Tobias Lenz

We develop the foundations of -global homotopy theory as a synthesis of classical equivariant homotopy theory on the one hand and global homotopy theory in the sense of Schwede…

math.AT2020★ 3 cited

On the global homotopy theory of symmetric monoidal categories

Tobias Lenz

Parsummable categories were introduced by Schwede as input for his global algebraic -theory construction. We prove that their whole homotopy theory with respect to the so-called…

math.CT2020

Parsummable categories as a strictification of symmetric monoidal categories

Tobias Lenz

We prove that the homotopy theory of parsummable categories (as defined by Schwede) with respect to the underlying equivalences of categories is equivalent to the usual homotopy th…

math.AT2017★ 6 cited

Homotopy (Pre-)Derivators of Cofibration Categories and Quasi-Categories

Tobias Lenz

We prove that the homotopy prederivator of a cofibration category is equivalent to the homotopy prederivator of its associated quasi-category of frames, as introduced by Szumiło. W…