The traditional model of sequential decision making, for instance, in extensive form games, is a tree. Most texts define a tree as a connected directed graph without loops and a distinguished node, called the root. But an abstract graph is not a domain for decision theory. Decision theory...

This paper provides a self-contained definition and a characterization of the class of extensive form games that are adequate for applications, but still do not employ any finiteness assumptions. In spite of its simplicity, the resulting definition is more general than the classical ones....

This paper addresses the question of what it takes to obtain a well-defined extensive form game. Without relying on simplifying finiteness or discreteness assumptions, we characterize the class of game trees for which all pure strategy combinations induce unique outcomes. The generality of the...