VF — Avoid cycles or otherwise meaningless relationships.

It is currently possible that cyclical patterns occur in Role Assignments. These should be avoided. It should also be avoided that a Role provides a Value Proposition to itself, as this has no real meaning.

Include meta-model constraints in relation to Assignment, Collaboration, ValueProposition and ValueElement

Include the following meta-model constraints: 1) A Role MUST NOT be assigned itself (directly, or indirectly via other Assignments). 2) A Role MUST not be assigned its containing Collaboration. 3) The provider of a ValueProposition MUST NOT be the recipient of that ValueProposition..