DEFINITION flt_trans()
TYPE =
       ∀c1:C.∀c2:C.∀t1:T.∀t2:T.(flt c1 t1 c2 t2)→∀c3:C.∀t3:T.(flt c2 t2 c3 t3)→(flt c1 t1 c3 t3)
BODY =
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