include "logic/pts.ma".
-ninductive bool: Type[0] ≝
- true: bool
- | false: bool.
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+ninductive bool: Type[0] ≝ true: bool | false: bool.
+
+ndefinition orb ≝ λa,b:bool. match a with [ true ⇒ true | _ ⇒ b ].
+
+notation "a || b" left associative with precedence 30 for @{'orb $a $b}.
+interpretation "orb" 'orb a b = (orb a b).
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