lean2/library/logic/axioms/em.lean
2015-05-23 20:52:23 +10:00

11 lines
304 B
Text
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

/-
Copyright (c) 2015 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
Excluded middle
Remark: This axiom can be derived from propext funext and hilbert.
See examples/diaconescu
-/
axiom em (a : Prop) : a ¬a