main emphasis on models and functions
less emphasis on logics
more emphasis on abstract/pure mathemtics
The Irish VDM is a member of the VDM family, but is not compliant with the VDM-SL standard.
from foreword to VDM'87 Proceedings [1]:
"Foundations: as with all formal methods, VDM's mathematical foundations must be sound and complete. By its very nature, which is essentially mathematical, VDM will contiue to evolve. There are open areas of research which need to be addressed. There are explicit relationships with other branches of mathematics that need to be elaborated."