VDM
A FormalLanguage based on DenotationalSemantics.
VDM is a generic term indicating different dialects and methodologies originated in the work of HeinzZemanek? in the ViennaIbmLaboratory?
Currently, VDM-SL (VDM specification language) is the ISO and BSI standard.
A VDM specification is built upon two models. The representational abstraction, equivalent to a data model, and the operational abstraction, equivalent to a program, that can be done in a declarative of in a imperative way.
Documented in "Systematic Software Development Using VDM" by C.B. Jones
Based around pre- and post- conditions. I assume BertrandMeyer was aware of this when he designed EiffelLanguage.
--PaulHudson (a VDM fan. Once worked in the same company as C. B. Jones, but no VDM used there :-()
VDM uses ThreeValuedLogic.