I agreed that the word cardinality is too difficult, couldn't come up with a simpler one yet. The property is actually a requirement on the 'deployment cardinality', specifically a range. 
So I'd like to convey that it is about the number of deployeds (mapped from the deployable), ``mappingRequirement`` or ``mappingSpecification`` don't do that. 
Maybe ``mustBeMapped`` and adjusting the values to NEVER, OPTIONALLY, AT_LEAST_ONCE, EXACTLY_ONCE, MULTIPLE_TIMES?