Association and Property - some cases Gallery Tutorial TRAIL: Webel's ultimate guide to Systems Modeling Language (v1) with MagicDraw/Cameo Section 01:02: UML 101 for model-based systems engineering with SysML Slide kind UML Class Diagram
These multiplicities may be assumed if not shown on a diagram. To avoid confusion, any multiplicity other than the default should always be shown on a diagram. Source OMG Systems Modeling Language (SysML) 1.7beta1
A part or shared association has a default multiplicity of [0..1] on the black or white diamond end. A unidirectional association has a default multiplicity of 1 on its target end. Source OMG Systems Modeling Language (SysML) 1.7beta1
The semantics are undefined for adding a value that violates the upper multiplicity of the StructuralFeature, and for adding a new value to a StructuralFeature with isReadonly=true after initialization of the object that would have the value. Source Unified Modeling Language 2.5.1