UMLR — UML 2.3 Infra 12 Incomplete conformance for infinity

Issue 15780 for OCL suggests resolving the inconsistent definition of
UnlimitedNatural
by defining '' infinity (and '-' minus infinity) as valid Integer and Real
values.

This is appropriate to resolve the anomally that

Integer conformsTo Real so any Integer is a valid Real,
UnlimitedNatural conformsTo Integer so any UnlimitedNatural is a valid
Integer

except that at present '*' is a valid UnlimitedNatural without a valid
Integer
or Real counterpart.

The resolution of Issue 14196, introducing UnlimitedNatural to the OCL
specification, indicates that any use of UnlimitedNatural '*' as an Integer
or Real requires a conversion to invalid. This imposes an undesirable
implementation burden in addition to the anomalous conformance behaviour.

Therefore please add '' (and '-') to Integer and Real.