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Kirkman's schoolgirl problem is a problem in combinatorics proposed by Rev. Thomas Penyngton Kirkman in 1850 as Query VI in ''The Lady's and Gentleman's Diary'' (pg.48). The problem states:
== Solution == If the girls are numbered from 01 to 15, the following arrangement is one solution:〔 A solution to this problem is an example of a ''Kirkman triple system'', which is a Steiner triple system having a ''parallelism'', that is, a partition of the blocks of the triple system into parallel classes which are themselves partitions of the points into disjoint blocks. There are seven non-isomorphic solutions to the schoolgirl problem. Two of these are ''packings'' of the finite projective space PG(3,2). A packing of a projective space is a partition of the lines of the space into ''spreads'', and a spread is a partition of the points of the space into lines. These "packing" solutions can be visualized as relations between a tetrahedron and its vertices, edges, and faces. A square, rather than tetrahedral, model may also be used: For the origin of the square model, see the (Cullinane diamond theorem ). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Kirkman's schoolgirl problem」の詳細全文を読む スポンサード リンク
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