Specifying <Property Value> Instances
In the current example, the <Union Of Primitive Geometry> has two <Property Value> components.
This is unambiguous, because the <Property Value> instances in this case comply with the <<No Attribute Conflicts>> constraint. That is, they're specifying values for different attributes — EAC_VEGETATION_TYPE and EAC_SOIL_SURFACE_TEMPERATURE — rather than conflicting values for the same attribute.