(Inherited-Facet-Value Slot-Value-Type
Elevator
Elevator.Mbeam
Machine_Beam_Model)
(<= (Has-Parameter-Slot $X Machine_Beam_Unit_Weight)
(Machine_Beam_Model $X))
(<= (Has-Parameter-Slot $X Machine_Beam_Section_Modulus)
(Machine_Beam_Model $X))
(=> (Elevator.Mbeam $X $Y) (Machine_Beam_Model $Y))