Elements of -Category Theory

Description

The language of -categories provides an insightful new way of expressing many results in higher-dimensional mathematics but can be challenging for the uninitiated. To explain what exactly an -category is requires various technical models, raising the question of how they might be compared. To overcome this, a model-independent approach is desired, so that theorems proven with any model would apply to them all. This text develops the theory of -categories from first principles in a model-independent fashion using the axiomatic framework of an -cosmos, the universe in which -categories live as objects. An -cosmos is a fertile setting for the formal category theory of -categories, and in this way the foundational proofs in -category theory closely resemble the classical foundations of ordinary category theory. Equipped with exercises and appendices with background material, this first introduction is meant for students and researchers who have a strong foundation in classical 1-category theory.

Emily Riehl is an associate professor of mathematics at Johns Hopkins University. She received her PhD from the University of Chicago and was a Benjamin Peirce and NSF postdoctoral fellow at Harvard University. She is the author of Categorical Homotopy Theory (Cambridge, 2014) and Category Theory in Context (2016), and a co-author of Fat Chance: Probability from 0 to 1 (Cambridge, 2019). She and her present co-author have published ten articles over the course of the past decade that develop the new mathematics appearing in this book. Dominic Verity is a professor of mathematics at Macquarie University in Sydney and is a director of the Centre of Australian Category Theory. While he is a leading proponent of 'Australian-style' higher category theory, he received his PhD from the University of Cambridge and migrated to Australia in the early 1990s. Over the years he has pursued a career that has spanned the academic and non-academic worlds, working at times as a computer programmer, quantitative analyst, and investment banker. He has also served as the Chair of the Academic Senate of Macquarie University, the principal academic governance and policy body.

'The book of Riehl and Verity is altogether a pedagogical introduction, a unified presentation and a foundation of higher category theory. The theory of -cosmoi is an elegant way of organising and developing the subject. The extension of category theory to -categories is by itself a miracle, vigorously presented in the book.' Andre Joyal, Universite du Quebec a Montreal 'Emily and Dom have done what many thought impossible: they have written an introductory text on a model-independent approach to higher category theory. This self-contained text is ideal for both end-users and architects of higher category theory. Every page is bursting at the seams with gorgeous insights and the refreshingly candid delight the authors take in their subject.' Clark Barwick, University of Edinburgh 'This remarkable book starts with the premise that it should be possible to study -categories armed only with the tools of 2-category theory. It is the result of the authors' decade-long collaboration, and they have poured into it all their experience, technical brilliance, and expository skill. I'm sure I'll be turning to it for many years to come.' Steve Lack, Macquarie University