not be interpreted as representing the o cial policies, either expressed or implied, of NSF or the U.S. Government. This thesis describes the design of a meta-logical framework that supports the representation and veri cation of deductive systems, its implementation as an automated theorem prover, and experimental results related to the areas of programming languages, type theory, and logics. Design: The meta-logical framework extends the logical framework LF [HHP93] by a meta-logic M + 2. This design is novel and unique since it allows higher-order encodings of deductive systems and induction principles to coexist. On the one hand, higher-order representation techniques lead to concise and direct encodings of programming languages and logic calculi. Inductive de nitions on the other hand allow the formalization of properties about deductive systems, such as the proof that an operational semantics preserves types or the proof that a logic is is a proof calculus whose proof terms are recursive functions that may be consistent.M +

In this paper we present a framework for the definition of generic and thus reusable tactics. We present an extension of the window inference technique which is the formal basis of a hierarchical, problem-reduction style of reasoning. The window inference technique is analyzed and general reasoning rules are separated from logic specific rules. The separation between logic specific and general rules is used to define a framework offering generic window reasoning rules to allow for the definition of generic tactics, where logic specific parts are separated from the tactic level. 1 Introduction Interactive theorem proving systems are used to support strict mathematical reasoning wrt. different logics, as for example classical first-order logic, higher-order logic or modal logics. These systems are either meta-logical systems allowing the declarative encoding of a large variety of logics or they are "multi-logical" systems, where the different logics are build into the system on t...