Theorem Prover Support for the Refinement of Stream Processing Functions

In this paper we show how to use the theorem prover Isabelle to provide tool support for Focus a speci cation and veri cation frame work for the stepwise development of distributed systems Focus is em bedded into Isabelle by modeling the basic notion of stream processing functions and by formalizing an appropriate set of assumption commit ment re nement rules Moreover the re nement calculus is proven to be correct within this model The model is based upon the logic HOLCF an extension of higher order logic by the notions of domain theory The well known case study of a production cell is used to evaluate our proof support by mechanically verifying parts of a paper and pencil proof