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Higher Topos Theory

mathematics

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higher category theory

Contents

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(∞,1)-topos theory

Contents

characterization of (∞,1)-toposes

constructions in (∞,1)-toposes

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model category

definition

constructions

refinements

presentation of

(

,1

)

-categories

model structures

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This entry is about the book

which discusses the higher category theory of (∞,1)-categories in general and that of (∞,1)-categories of (∞,1)-sheaves (i.e. of ∞-stacks) – called (Grothendieck-Rezk-Lurie) (∞,1)-toposes – in particular.

Contents

Related entries

For general information on higher category and higher topos theory see also

If you need basics, see

If you need more motivation see

If you need to see applications see for instance

Summary

General idea

Recall the following familiar 1-categorical statement:

One can think of Lurie’s book as a comprehensive study of the generalization of the above statement from 1 to (,1) (recall the notion of (n,r)-category):

First part, sections 1-4

Based on work by André Joyal on the quasi-category model for (∞,1)-categories, Lurie presents a comprehensive account of the theory of (∞,1)-categories including the definitions and properties of all the standard items familiar from category theory (limits, fibrations, etc.)

Second part, sections 5-7

Given the (,1)-categorical machinery from the first part there are natural (,1)-categorical versions of (,1)-presheaf and (,1)-sheaf categories (i.e. (,1)-categories of ∞-stacks): the ”-topoi” that give the book its title (more descriptively, these would be called “Grothendieck (,1)-topoi”). Lurie investigates their properties in great detail and thereby in particular puts the work by Brown, Joyal, Jardine, Toën on the model structure on simplicial presheaves into a coherent (,1)-categorical context by showing that, indeed, these are models for ∞-stack (∞,1)-toposes.

How to read this book

General remark

Don’t be put-off by the sheer size. On top of everything else, Lurie is a great expositor.

1-categorical background

The book Higher topos theory together with Lurie’s work on Stable ∞-Categories is close to an (,1)-categorical analog of the 1-categorical material as presented for instance in

Sections with crucial concepts

The book discusses crucial concepts and works out plenty of detailed properties. On first reading it may be helpful to skip over all the technical parts and pick out just the central conceptual ideas. These are the following:

Content

1 An overview of higher category theory

2 Fibrations of Simplicial Sets

3 The -Category of -Categories

4 Limits and Colimits

5 Presentable and Accessible -Categories

5.1 (,1)-categories of presheaves

5.2 adjoint (,1)-functors

5.3 (,1)-categories of inductive limits

5.4 accessible (,1)-categories

5.5 presentable (,1)-categories

6 -Topoi

6.1 Definitions and characterizations

6.2 Constructions of (,1)-toposes

6.4 n-Topoi

6.5 Homotopy theory in an (,1)-topos

7 Higher Topos Theory in Topology

7.1 Paracompact spaces

7.2 Dimension theory

Appendix

Category theory

Model categories

Simplicial model categories

category: reference