DTV12 — DTV Issue: OCL in clause 8.2.1

The only OCL Constraint in DTV clause 8.2.1 reads:

context: _'time interval'

inv: 'time interval'.'time interval1 is proper part of time interval2'-->notEmpty()

It should be:

context: _'time interval'

inv: self._'time interval1 is proper part of time interval2'-->notEmpty()

(The first word after the “inv:” in the second line should be “self”, not “_’time_interval’”.)

The RTF agrees that the OCL is incorrect. Interpretation of the corrected OCL, however, seems to require any conforming M0 population of the UML/MOF model to be infinite, in that each ‘time interval’ object must have different ‘proper part’ time interval. The intent of the Axiom is that no time interval can be declared or assumed to be atomic, but in any given model population there will be time intervals that have no proper part in the population. The proposed OCL constraint would make such a population invalid.