Book Review: The Markoff and Lagrange spectra
Jeffrey D. Vaaler · Bulletin of the American Mathematical Society · 1991
may lead to a complete solution of Bannai's problem to determine all éf-polynomial DRGs of diameter > 2.There is no doubt that the book under review will be an essential tool for the specialists in discrete mathematics.But also the general mathematician may take advantage of the ideas expressed in the book.To illustrate this we recall that in the very first line of this review we spoke of regularity, and not of symmetry of the platonic solids.Indeed, the book is devoted to graphs having well-defined regularity properties.In the group case regularity actually can be interpreted as symmetry.This is important for two reasons.Group theory provides many examples of nice graphs; and algebraic graph theory sometimes provides interesting results about groups.