-- Copyright (c) 2014 Microsoft Corporation. All rights reserved. -- Released under Apache 2.0 license as described in the file LICENSE. -- Author: Jeremy Avigad, Floris van Doorn -- Empty type -- ---------- import logic.cast inductive empty : Type namespace empty protected theorem elim (A : Type) (H : empty) : A := rec (λe, A) H protected theorem subsingleton [instance] : subsingleton empty := subsingleton.intro (λ a b, !elim a) end empty