D-structures and their semantics

Many logicians are familiar with the game theoretic approach to semantics, due to Jaakko Hintikka. This paper by me contains class notes of a logic course at Boston University in fall 1972. It has similar game theoretic ideas, developed quite independently, but influenced by the work of A. Ehrenfeucht. It applies to a larger class of logics, including classical logic, intuitionistic logic and the *-semantics of Ehrenfeucht. The treatment is via D-structures which are finite approximations of infinite structures. For various reasons I did not publish this paper then, but some abstracts, both by myself as well as joint abstracts with Dick De Jongh, Nick Goodman and John Mayberry WERE published in 1972 in the notices of the AMS as well as the Journal of Symbolic Logic. The paper itself finally appeared in the volume to celebrate the 50th birthday of Johan van Benthem

Theory of Collective Action

Theory predicts that when people pursue their selfish aims then it leads to suboptimal outcomes for society or to the group they belong to. The prisoner\u27s dilemma and the tragedy of the commons are classic examples. In her presidential lecture to the American Political Science Association Elinor Ostrom examined this fact and also noted that in practice people do not always follow the suboptimal strategy. What does she suggest? This document consists of slides I created giving an account of her paper. She had not won the Nobel when she gave this talk but it was conferred on her later