INDUCTIVE DEFINITION fsubst0 () [ :nat, :T, :C, :T ]
OF ARITY CTProp
BUILT FROM:
     fsubst0_snd: t2:T.(subst0 i v t1 t2)(fsubst0 i v c1 t1 c1 t2)
   | fsubst0_fst: c2:C.(csubst0 i v c1 c2)(fsubst0 i v c1 t1 c2 t1)
   | fsubst0_both: t2:T.(subst0 i v t1 t2)c2:C.(csubst0 i v c1 c2)(fsubst0 i v c1 t1 c2 t2)