7.2.69 Valency principle

• identifier: principle.valency
• dimension variables: D
• argument variables:
  In: valency(label(D))
Out: valency(label(D))
• default values:
  In: _.D.entry.in
Out: _.D.entry.out
• model record: empty
• constraints: In1 (priority 130), Out (priority 130)

This principle combines the In1 principle (In1) and the Out principle (Out) in one, and is thus easier to use.