DEFINITION sc3_bind()
TYPE =
       g:G
         .b:B
           .not (eq B b Abst)
             a1:A
                  .a2:A
                    .vs:TList
                      .c:C
                        .v:T
                          .t:T
                            .(sc3
                                g
                                a2
                                CHead c (Bind b) v
                                THeads (Flat Appl) (lifts (S OO vs) t)
                              (sc3 g a1 c v
                                   sc3 g a2 c (THeads (Flat Appl) vs (THead (Bind b) v t)))
BODY =
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