-let rec lweight (a: A) on a: nat \def match a with [(ASort _ _) \Rightarrow O
-| (AHead a1 a2) \Rightarrow (S (plus (lweight a1) (lweight a2)))].
+rec definition lweight (a: A) on a: nat \def match a with [(ASort _ _)
+\Rightarrow O | (AHead a1 a2) \Rightarrow (S (plus (lweight a1) (lweight
+a2)))].