This is the first book on elliptic quantum groups, i.e., quantum groups
associated to elliptic solutions of the Yang-Baxter equation. Based on
research by the author and his collaborators, the book presents a
comprehensive survey on the subject including a brief history of
formulations and applications, a detailed formulation of the elliptic
quantum group in the Drinfeld realization, explicit construction of both
finite and infinite-dimensional representations, and a construction of
the vertex operators as intertwining operators of these representations.
The vertex operators are important objects in representation theory of
quantum groups. In this book, they are used to derive the elliptic q-KZ
equations and their elliptic hypergeometric integral solutions. In
particular, the so-called elliptic weight functions appear in such
solutions. The author's recent study showed that these elliptic weight
functions are identified with Okounkov's elliptic stable envelopes for
certain equivariant elliptic cohomology and play an important role to
construct geometric representations of elliptic quantum groups.
Okounkov's geometric approach to quantum integrable systems is a rapidly
growing topic in mathematical physics related to the Bethe ansatz, the
Alday-Gaiotto-Tachikawa correspondence between 4D SUSY gauge theories
and the CFT's, and the Nekrasov-Shatashvili correspondences between
quantum integrable systems and quantum cohomology. To invite the reader
to such topics is one of the aims of this book.