<abstract xml:lang="en" xmlns="http://www.w3.org/1999/xhtml"><p>The article provides counting derangements of finite sets and counting non bijective functions. We provide a recursive formula for the number of derangements of a finite set, together with an explicit formula involving the number e. We count the number of non-one-to-one functions between to finite sets and perform a computation to give explicitely a formalization of the birthday problem. The article is an extension of [10].</p></abstract>

The article provides counting derangements of finite sets and counting non bijective functions. We provide a recursive formula for the number of derangements of a finite set, together with an explicit formula involving the number e. We count the number of non-one-to-one functions between to finite sets and perform a computation to give explicitely a formalization of the birthday problem. The article is an extension of [10].

Counting Derangements, Non Bijective Functions and the Birthday Problem

Institut für Informatik I4, Techische Universität München, Boltzmannstraße 3 85748 Garching, Germany

Formalized Mathematics

{"article-title":"Counting Derangements, Non Bijective Functions and the Birthday Problem"}

The article provides counting derangements of finite sets and counting non bijective functions. We provide a recursive formula for the number of derangements...

Counting Derangements, Non Bijective Functions and the Birthday Problem

Published Online: Jan 05, 2011

Page range: 197 - 200

DOI: https://doi.org/10.2478/v10037-010-0023-9

This content is open access.