411 REFERENCE · Wiktionary
Kirkman's schoolgirl problem
Reference material by Wiktionary contributors. This retains its source identity and is not 411 news reporting.
English
Etymology
Proposed by Rev. Thomas Penyngton Kirkman in 1850.
Proper noun
en math A problem in combinatorics, in which 15 schoolgirls go walking three abreast for seven days in succession, and must be arranged so that no two walk abreast more than once.
en eponyms