Memoirs is a series devoted to the publication of research in all areas of pure and applied mathematics. Manuscripts accepted for publication are similar in nature to those published in Transactions of the American Mathematical Society and meet the same editorial requirements. To be accepted by the editorial board, manuscripts must be correct, new, and significant. Further, they must be well-written and of interest to a substantial number of mathematicians. Each issue contains either a single monograph or a group of related papers. The 2005 subscription consists of six mailings, each typically containing four or more numbers. Printed format.