A General Proof Rule for Procedures in Predicate Transformer SemanticsMartin, Alain J (1983) A General Proof Rule for Procedures in Predicate Transformer Semantics. Technical Report. California Institute of Technology. [CaltechCSTR:1983.5075-tr-83] Full text available as:
AbstractGiven a general definition of the procedure call based on the substitution rule for assignment, a general proof rule is derived for procedures with unrestricted value, result, and value- result parameters, and global variables in the body of the procedure. It is then extended for recursive procedures. Assuming that it has been proved that the body establishes a certain postcondition I, the intention, for a certain precondition J, the proof rule permitting to determine under which conditions a certain procedure call establishes the post condition E, the "extension", is based on finding an adaptation A , a s weak as possible, such that A ~ I -- E ( E ' is derived from E by some substitution of parameter variables.) It is preferable, but not essential, that the body be transparent for the value parameters, i.e . , that the value parameters are not changed by the body.
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