An interactive theorem prover, Isabelle, is under development. In LCF, each inference rule is represented by one function for forwards proof and another (a tactic) for backwards proof. In Isabelle, each inference rule is represented by a Horn clause.

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LIFE is an experimental programming language proposing to integrate logic programming, functional programming, and object-oriented programming. It replaces first-order terms with ψ-terms, data structures which allow computing with partial information. These are approximation structures denoting sets of values. LIFE further enriches the expressiveness of ψ-terms with functional dependency constraints. We must explain the meaning and use of functions in LIFE declaratively as solving partial information constraints. These constraints do not attempt to generate their solutions but behave as demons filtering out anything else.

Garbage Collection frees the programmer from the burden of explicitly deallocating unused data. This facility induces a considerable overhead but also causes some delays that may affect real-time applications. Guaranteed throughput (with at most short and predictable delays) is needed in many applications such as plane or plant control and requires at least a worst case analysis to identify the performances of the whole system. Traditional GC are made of two phases : the marker which identifies all useful data, followed by the sweeper which reclaims all useless data. On-the-fly GC schemes were introduced to permit an application and a collector to run concurrently. That concurrency may lessen the GC penalty incurred by the application. We present here a new algorithm where the application, the marker and the sweeper are concurrent. The benefit is to tightly adjust collection rate to application consumption and have an allocation time bounded by a small constant. Moreover our algorithm ...