CADiZ

Reference manual / Z-related commands / Proof management commands / exists conjecture


The exists conjecture command is applicable to (generic) axiomatic paragraphs, including global constraints. It generates a conjecture that values can be found for the paragraph's variables that satisfy the constraints on them. The conjecture will be provable only if the paragraph is a conservative extension. (This command should perhaps be applicable to free type paragraphs too, but isn't.)

Schema paragraphs are excluded from the above as they always have a value, even if it is only the relevant empty set of bindings. The exists conjecture command can nevertheless be applied to schema paragraphs, but instead generates the conjecture that there is a value in the the set of bindings denoted by the paragraph. This is in general not a proof obligation, but is sometimes useful, e.g. for showing that an initialization schema generates a valid initial state.


IT 3-Jun-1998