DEFINITION ty3_gen_appl()
TYPE =
       ∀g:G
         .∀c:C
           .∀w:T
             .∀v:T
               .∀x:T
                 .ty3 g c (THead (Flat Appl) w v) x
                   →(ex3_2
                        T
                        T
                        λu:T.λt:T.pc3 c (THead (Flat Appl) w (THead (Bind Abst) u t)) x
                        λu:T.λt:T.ty3 g c v (THead (Bind Abst) u t)
                        λu:T.λ:T.ty3 g c w u)
BODY =
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