UTP12 — OCL expressions should be used for precise description of constraints

Rational
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OCL is the OMG’s formal, MOF-based language to express fine-grained constraints in MOF-based models. OCL expressions are unambiguous, precise and computable.

Issue
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All constraints in UTP specification are defined with natural language. In order to help readers (tool vendors, tester, modeler) to implement, understand and apply the stereotypes of UTP properly, it would be helpful to use formal OCL expressions for these constraints. The natural language description may remain in the specification, meaning the OCL supplements the already existing description. The benefits would be two-folded: Both readers with and without OCL knowledge would be able to understand the specification.
UML 2.3 Superstructure, section 18.3.2 Extension, subsection Semantics explains how OCL constraints can be exploited to define restriction on the extended metaclass.