Towards a Better Definition of Transactions

This report describes research done at the Artificial Intelligence Laboratory of the Massachusetts Institute of Technology. Support for the laboratory's artificial intelligence research is provided in part by the Office of Naval Research of the Department of Defense under Contract N00014-75-C-0522.This paper builds on a technical report written by Carl Hewitt and Henry Baker called "Actors and Continuous Functionals". What is called a "goal-oriented activity" in that paper will be referred to in this paper as a "transaction". The word "transaction" brings to mind an object closer in function to what we wish to present than does the word "activity". This memo, therefore, presents the definitions of a reply and a transaction as given in Hewitt and Baker's paper and points out some discrepancies in their definitions. That is, that the properties of transactions and replies as they were defined did not correspond with our intuitions, and thus the definitions should be changed. The issues of what should constitute a transaction are discussed, and a new definition is presented which eliminates the discrepancies caused by the original definitions. Some properties of the newly defines transactions are discussed, and it is shown that the results of Hewitt and Baker's paper still hold given the new definitions.MIT Artificial Intelligence Laboratory Department of Defense Office of Naval Researc