INDUCTIVE DEFINITION sty1 () [ :G, :C, :T ]
OF ARITY TProp
BUILT FROM:
     sty1_sty0: t2:T.(sty0 g c t1 t2)(sty1 g c t1 t2)
   | sty1_sing: t:T.(sty1 g c t1 t)t2:T.(sty0 g c t t2)(sty1 g c t1 t2)