Maria Paola Bonacina, Thierry Boy de la Tour
2005 Electronical Notes in Theoretical Computer Science  
Preface Strategies are ubiquitous in automated deduction, because the inference rules at the heart of reasoning systems are typically non-deterministic in nature, and need to be complemented by another component, usually called strategy or search plan, which is responsible for the control of the inference rules. In automated theorem proving, the search plan selects inference rule and premises for the next step in the derivation, which involves priorities on inferences rules, heuristics to sort
more » ... ormulae or subgoals, and criteria, also typically heuristic in nature, to prune the search space. In rewriting engines, the rewriting strategy selects redex and rule for the next step. Similar considerations apply to decision procedures, model building methods, SAT or QBF solvers. In interactive systems, tactics define conditions for the application of inference rules, and tacticals control the application of tactics. It is still the control component of the proof assistant that is responsible for requesting the user to instantiate variables, or select lemmas. Not only strategies are necessary to turn a non-deterministic inference system into a mechanical procedure, but they play a central role in making the procedure efficient, and capable of solving problems of practical interest. Most deduction paradigms (generation of consequences, subgoal-reduction, generation of instances, case analysis, enumeration) generate huge spaces of choices, so that sophisticated strategies are essential to implement them efficiently. This is as true as ever today, when a major challenge is the integration of paradigms and procedures, to create automated reasoning environments for applications such as verification. Combining theorem proving and model finding, or SAT solvers and decision procedures, proof assistants and theorem provers, just to name a few, poses all sorts of control problems to be solved in the definition, design and implementation of strategies. The series of workshops on "Strategies in Automated Deduction," or STRA-
doi:10.1016/j.entcs.2005.02.001 fatcat:k5whorbw2vgnxp7st4q2ll42ay