[Moose-dev] Expressing that a property is mandatory

Hi, I can't see how Fame enable to express that a Property in a metamodel is mandatory or not. The isMultivalued property of the FM3PropertyDescription class enables to specify that a property is multivalued or not, but nothing concerning the character mandatory of the property. Saying that in other words, it is possible to specify in a metamodel that the upper multiplicity of a property is '*' but I can't see how to specify the lower multiplicity. For example considering the metamodel of stateMachine. A State is contained in one and only one StateMachine, whereas a StateMachine can contained 0 or several states. A transition has one and only one State as source and a state can be the source of 0 or several transitions. Does Fame enable to express this mandatory characteristic? Expressing such a thing may facilitate some generations. Indeed, when adding a State, we must specify its container but it is not mandatory to specify the transitions for which it is a source. Thank you in advance for your help. Anne