Ray Reiter - A Memoir.- 1 The Early Years I: High school.- 2 The Early Years II: The University of Toronto.- 3 The Middle Years I: The University of Michigan.- 4 The Middle Years II: The University of British Columbia.- 5 A Reiter Aphorism.- 6 A Reiter Aphorism.- 7 The Middle Years III: The University of Toronto (Again).- 8 The Future.- Default Logic and Purity of Reasoning.- 1 An overview of Default Logic.- 2 The logical nature of reasoning.- 3 The modal logics of Default Logic.- 4 Default Logic: a strategy for explicit Definability.- 5 Default Logic: from a single to multiple Contexts.- Computing Domain Specific Information.- 1 Introduction.- 2 The Logistics Domain.- 3 Conversion to Successor State Axioms.- 4 Inner and Outer Boundaries.- 5 Some Examples.- 6 Conclusion.- Specifying Database Transactions and Active Rules in the Situation Calculus.- 1 Introduction.- 2 Active Rules.- 3 Specifying Database Updates.- 4 Specifying Transactions.- 5 Representing Active Rules.- 6 Reasoning from the Specification.- 7 Conclusions and Further Work.- The Frame Problem and Bayesian Network Action Representations.- 1 Introduction.- 2 Actions: Semantics and Basic Representations.- 3 Single Actions: Structure and the Frame Problem.- 4 Multiple Actions: The Frame and Ramification Problems.- 5 Concluding Remarks.- Philosophical and Scientific Presuppositions of Logical Al.- 1 Philosophical Presuppositions.- 2 Scientific Presuppositions.....76.- On Existence of Extensions for Default Theories.- 1 Introduction.- 2 Necessary and sufficient conditions for the existence of extensions.- 3 An interpretation of default rules using object-meta pairs.- 4 Appendix.- An Incremental Interpreter for High-Level Programs with Sensing.- 1 Introduction.- 2 Preliminaries.- 3 Off-line lookahead.- 4 Characterizing on-line executions.- 5 An incremental interpreter.- 6 Discussion.- An Improved Incremental Algorithm for Generating Prime Implicates.- 1 Introduction.- 2 A brute-force algorithm.- 3 Improving efficiency.- 4 Results.- Fixpoint 3-valued Semantics for Autoepistemic Logic.- 1 Introduction.- 2 Autoepistemic logic - preliminaries.- 3 A fixpoint 3-valued semantics for autoepistemic logic.- 4 An effective implementation of V.- 5 Relationship to logic programming.- 6 Conclusions and future work.- Toward Efficient Default Reasoning.- 1 Computation and Nonmonotonicity.- 2 Sufficient Tests for Consistency.- 3 Context-Limited Consistency Checking.- 4 The Mitigating Nature of Defaults.- 5 Experimental Evaluation.- 6 Related Work.- 7 Conclusions and Open Problems.- 8 Acknowledgments.- Action, Time and Default.- Explanatory Diagnosis: Conjecturing Actions to Explain Observations.- 1 Introduction.- 2 Representation Scheme.- 3 Preliminaries.- 4 Explanatory Diagnosis.- 5 Exploiting Regression.- 6 Exploiting the Task.- 7 Related Work.- 8 Summary.- On Sensing and Off-line Interpreting in GOLOG.- 1 Introduction.- 2 The Situation Calculus.- 3 GOLOG.- 4 Conditional action trees.- 5 sGOLOG.- 6 A simple implementation.- 7 Summary and discussion.- Reactivity in a Logic-Based Robot Programming Framework (Extended Version).- 1 Introduction.- 2 ConGolog.- 3 Interfacing the High-Level Control Module.- 4 A Mail Delivery Example.- 5 Experimentation.- 6 Discussion.- A Additional Axioms and Procedure Definitions.- Success of Default Logic.- Search Algorithms in the Situation Calculus.- 1 Dedication.- 2 Introduction.- 3 Search Problems and Algorithms.- 4 The Situation Calculus.- 5 Search Problems in the Situation Calculus.- 6 Search Algorithms in the Situation Calculus.- 7 Depth-First Search.- 8 Breadth-First Search.- 9 Best-First Search.- 10 Conclusions.- Logic and Databases: a 20 Year Retrospective - Updated in Honor of Ray Reiter.- 1 Introduction.- 2 Intellectual Contributions of Deductive Databases.- 3 Implementation Status of Deductive Databases.- 4 Emerging Areas and Trends.- 5 Summary.- Action Inventory for a Knowledge-Based Colloquium Agent. Preliminary Version.- 1 The Electronic Colloquium.- 2 Additional application aspects.- 3 Some examples of tasks.- 4 Agent support for electronic colloquia.- 5 Present organization of the colloquium software.- 6 States and Actions in the Colloquium Domain.- 7 Discussion.- A GOLOG Specification of a Hypertext System.- 1 Introduction.- 2 The Situation Calculus.- 3 Hypertext.- 4 GOLOG: Complex Actions.- 5 Run-time Layer.- 6 Conclusions and Future Work.- Explanation Closure, Action Closure, and the Sandewall Test Suite for Reasoning about Change.- 1 Introduction.- 2 DFL, TC, and the test scenarios.- 3 Coda: The Metaphysics of Change.- 4 Conclusion.- What Sort of Computation Mediates Best Between Perception and Action?.- 1 Introduction.- 2 Embodiment.- 3 Logic.- 4 Action and Change.- 5 Space, Noise and Perception.- 6 Planning, Sensing and Computation.- 7 The Sense-Plan-Act Cycle.- 8 An Implemented Robot Controller.- 9 Conclusion.- 10 Acknowledgments.- 11 Postscript: The Influence of Ray Reiter.- Modeling and Analysis of Hybrid Control Systems.- 1 Introduction.- 2 System Modeling in Constraint Nets.- 3 Requirements Specification in Timed V-Automata.- 4 Hybrid Control System Design.- 5 Behavior Verification Using Model Checking.- 6 Conclusions.