Ordered Sets: An Introduction with Connections from Combinatorics to Topology

Presents a wide range of material, from classical to brand new results Uses a modular presentation in which core material is kept brief, allowing for a broad exposure to the subject without overwhelming readers with too much information all at once Introduces topics by examining how they related to research problems, providing continuity among diverse topics and encouraging readers to explore these problems with research of their own The second edition of this highly praised textbook provides an expanded introduction to the theory of ordered sets and its connections to various subjects.  Utilizing a modular presentation, the core material is purposely kept brief, allowing for the benefits of a broad exposure to the subject without the risk of overloading the reader with too much information all at once.  The remaining chapters can then be read in almost any order, giving the text a greater depth and flexibility of use.  Most topics are introduced by examining how they relate to research problems, some of them still open, allowing for continuity among diverse topics and encouraging readers to explore these problems further with research of their own. A wide range of material is presented, from classical results such as Dilworth's, Szpilrajn's, and Hashimoto's Theorems to more recent results such as the Li-Milner Structure Theorem.  Major topics covered include chains and antichains, lowest upper and greatest lower bounds, retractions, algorithmic approaches, lattices, the dimension of ordered sets, interval orders, lexicographic sums, products, enumeration, and the role of algebraic topology.  This new edition shifts the primary focus to finite ordered sets, with results on infinite ordered sets presented toward the end of each chapter whenever possible.  Also new are Chapter 6 on graphs and homomorphisms, which serves to separate the fixed clique property from the more fundamental fixed simplex property as well as to discuss the connections and differences  between graph homomorphisms and order-preserving maps, and an appendix on discrete Morse functions and their use for the fixed point property for ordered sets. Topics Mathematical Logic and Foundations Order, Lattices, Ordered Algebraic Structures Combinatorics Algebraic Topology