Relative Category Theory and Geometric Morphisms

ISBN-13: 9780198534341 / Angielski / Twarda / 1992 / 276 str.

Jonathan Chapman; Frederick Rowbottom

Opis

Topos theory provides an important setting and language for much of mathematical logic and set theory. It is well known that a typed language can be given for a topos which allows a topos to be regarded as a category of sets. This enables a fruitful interplay between category theory and set theory.However, one stumbling block to a logical approach to topos theory has been the treatment of geometric morphisms. This book presents a convenient and natural solution to this problem by developing the notion of a frame relative to an elementary topos. The authors show how this technique enables a logical approach to be taken to topics such as category theory relative to a topos and the relative Giraud theorem.The work is essentially self-contained except that the authors presuppose a familiarity with basic category theory and topos theory.

Topos theory provides an important setting and language for much of mathematical logic and set theory. This book presents a convenient and natural solution to the treatment of geometric morphisms in this setting and shows how this may be applied to topics such as the relative Giraud theorem.

Recenzje

'The present book represents what must surely be an extreme point in the spectrum of possible approaches: the one which makes the greatest possible use of formal languages. The material, throughtout the books, is of a highly technical nature ... By providing a language adequate to handle indexed categories over a topos (and much more besides), the authors have done much to "demystify" indexed category theory and make it accessible to those for whom the sight of a 2-categorical diagram is liable to induce instant incomprehension. All such people ... should make the effort to master the technicalities in this book, if they wish to get closer to an understanding of what really goes on in the 2-category of toposes.' P.T. Johnstone, Zentralblatter, 1993

Spis treści

Introduction; Local set theories; Partial function theory `L'; Equationals; Categories in a topos; Topoi in a topos; A representation theorem for geometric morphisms; Local set theories in S; The theory of a topos in S; Topologies and sheaves; The relative Giraud theorem; Appendices.