The aim of this book is to present recently discovered connections between Artin's braid groups En and left self-distributive systems (also called LD systems), which are sets equipped with a binary operation satisfying the left self-distributivity identity x(yz) = (xy)(xz). (LD) Such connections appeared in set theory in the 1980s and led to the discovery in 1991 of a left invariant linear order on the braid groups. Braids and self-distributivity have been studied for a long time. Braid groups were introduced in the 1930s by E. Artin, and they have played an increas ing role in mathematics in view of their connection with many fields, such as knot theory, algebraic combinatorics, quantum groups and the Yang-Baxter equation, etc. LD-systems have also been considered for several decades: early examples are mentioned in the beginning of the 20th century, and the first general results can be traced back to Belousov in the 1960s. The existence of a connection between braids and left self-distributivity has been observed and used in low dimensional topology for more than twenty years, in particular in work by Joyce, Brieskorn, Kauffman and their students. Brieskorn mentions that the connection is already implicit in (Hurwitz 1891). The results we shall concentrate on here rely on a new approach developed in the late 1980s and originating from set theory. A: Ordering the Braids.- I. Braids vs. Self-Distributive Systems.- II. Word Reversing.- III. The Braid Order.- IV. The Order on Positive Braids.- B: Free LD-systems.- V. Orders on Free LD-systems.- VI. Normal Forms.- VII. The Geometry Monoid.- VIII. The Group of Left Self-Distributivity.- IX. Progressive Expansions.- C: Other LD-Systems.- X. More LD-Systems.- XI. LD-Monoids.- XII. Elementary Embeddings.- XIII. More about the Laver Tables.- List of Symbols.
"In this book...P. Dehornoy has accomplished with remarkable success the task of presenting the area of interaction where Artin's braid groups, left self-distributive systems (LD-systems) and set theory come together in a rigorous and clear manner...The exposition is self-contained and there are no prerequisites. A number of basic results about braid groups, self-distributive algebras, and set theory are provided."
--Mathematical Reviews
