INDUCTIVE DEFINITION
or4 ()
[
:Prop, :Prop, :Prop, :Prop
]
OF ARITY
Prop
BUILT FROM:
or4_intro0: P0→(or4 P0 P1 P2 P3)
| or4_intro1: P1→(or4 P0 P1 P2 P3)
| or4_intro2: P2→(or4 P0 P1 P2 P3)
| or4_intro3: P3→(or4 P0 P1 P2 P3)