C).(\lambda (t: T).(match a with [(ASort h n) \Rightarrow (land (arity g c t
(ASort h n)) (sn3 c t)) | (AHead a1 a2) \Rightarrow (land (arity g c t (AHead
a1 a2)) (\forall (d: C).(\forall (w: T).((sc3 g a1 d w) \to (\forall (is:
PList).((drop1 is d c) \to (sc3 g a2 d (THead (Flat Appl) w (lift1 is
C).(\lambda (t: T).(match a with [(ASort h n) \Rightarrow (land (arity g c t
(ASort h n)) (sn3 c t)) | (AHead a1 a2) \Rightarrow (land (arity g c t (AHead
a1 a2)) (\forall (d: C).(\forall (w: T).((sc3 g a1 d w) \to (\forall (is:
PList).((drop1 is d c) \to (sc3 g a2 d (THead (Flat Appl) w (lift1 is