Combinatorics of Finite Sets

It is the aim of this book to provide a coherent and up-to-date account of the basic methods and results of the combinatorial study of finite set systems. From its origins in a 1928 theorem of Sperner, this subject has become a lively area of combinatorial research, unified by the gradual discovery of structural insights and widely applicable proof techniques. Much of the material in the book concerns subsets of a set, but there are chapters dealing with more general partially ordered sets: for example, the Clements-Lindstr on extension of the Kruscal-Katona theorem to multisets is discussed, as is the Greene-Kleitman result concerning k-saturated chain partitions of general partially ordered sets. Connections with Dilworth's theorem, the marriage problem and probability are presented. Each chapter ends with a collection of exercises for which outline solutions are provided, and there is an extensive bibliography.