1_lower_is_0 A parameter with the «optional» stereotypes applied shall have multiplicity.lower equal to zero, otherwise multiplicity.lower shall be greater than zero Source OMG Systems Modeling Language (SysML) 1.6
When the «optional» stereotype is applied to parameters, the lower multiplicity shall be equal to zero. This means the parameter is not required to have a value for the activity or any behavior to begin or end execution ... Source OMG Systems Modeling Language (SysML) 1.6
