The Euler characteristic of a category

Leinster, T. (2008) The Euler characteristic of a category. Documenta Mathematica, 13, pp. 21-49.

Abstract

The Euler characteristic of a finite category is defined and shown to be compatible with Euler characteristics of other types of object, including orbifolds. A formula for the cardinality of the colimit of a diagram of sets is proved, generalizing the classical inclusion-exclusion formula. Both rest on a generalization of Mobius-Rota inversion from posets to categories.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Leinster, Dr Tom
• Authors: Leinster, T.
• Subjects: Q Science > QA Mathematics
• College/School: College of Science and Engineering > School of Mathematics and Statistics > Mathematics
• Journal Name: Documenta Mathematica
• ISSN: 1431-0635
• ISSN (Online): 1431-0643