This second edition of Lessons in Play reorganizes the presentation of the popular original text in combinatorial game theory to make it even more widely accessible. Starting with a focus on the essential concepts and applications, it then moves on to more technical material. Still written in a textbook style with supporting evidence and proofs, the authors add many more exercises and examples and implement a two-step approach for some aspects of the material involving an initial introduction, examples, and basic results to be followed later by more detail and abstract results. Features Employs a widely accessible style to the explanation of combinatorial game theory Contains multiple case studies Expands further directions and applications of the field Includes a complete rewrite of CGSuite material

Abstract: "In this paper we show that any system of equations over a free nilpotent group of class c is either unitary or nullary. In fact, such a system either has a most general solution (akin to the most general solution of a system of linear diophantine equations), or every solution has a proper generalization. In principle we provide an algorithm for determining whether or not a most general solution exists, and exhibiting it if it does. This requires solving a system of linear diophantine equations for approximately c(k over c) different right hand sides, where k is the number of parameters which occur in a most general solution of the system in the variety of abelian groups."

Abstract: "We consider the problem of characterizing the finitely additive probability measures on the definable subsets of the random graph which are invariant under the action of the automorphism group of this graph. We show that such measures are all integrals of Bernoulli measures (which arise from the coin-flipping model of the construction of the random graph). We also discuss generalizations to other theories."