lean2/library/logic/core/examples/instances_test.lean
2014-10-01 17:51:17 -07:00

47 lines
1.2 KiB
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) 2014 Microsoft Corporation. All rights reserved.
--- Released under Apache 2.0 license as described in the file LICENSE.
--- Author: Jeremy Avigad
import ..instances
open relation
open relation.general_operations
open relation.iff_ops
open eq.ops
section
theorem test1 (a b : Prop) (H : a ↔ b) (H1 : a) : b := mp H H1
end
section
theorem test2 (a b c d e : Prop) (H1 : a ↔ b) (H2 : a c → ¬(d → a)) : b c → ¬(d → b) :=
subst iff H1 H2
theorem test3 (a b c d e : Prop) (H1 : a ↔ b) (H2 : a c → ¬(d → a)) : b c → ¬(d → b) :=
H1 ▸ H2
end
theorem test4 (a b c d e : Prop) (H1 : a ↔ b) : (a c → ¬(d → a)) ↔ (b c → ¬(d → b)) :=
congruence.infer iff iff (λa, (a c → ¬(d → a))) H1
section
theorem test5 (T : Type) (a b c d : T) (H1 : a = b) (H2 : c = b) (H3 : c = d) : a = d :=
H1 ⬝ H2⁻¹ ⬝ H3
theorem test6 (a b c d : Prop) (H1 : a ↔ b) (H2 : c ↔ b) (H3 : c ↔ d) : a ↔ d :=
H1 ⬝ (H2⁻¹ ⬝ H3)
theorem test7 (T : Type) (a b c d : T) (H1 : a = b) (H2 : c = b) (H3 : c = d) : a = d :=
H1 ⬝ H2⁻¹ ⬝ H3
theorem test8 (a b c d : Prop) (H1 : a ↔ b) (H2 : c ↔ b) (H3 : c ↔ d) : a ↔ d :=
H1 ⬝ H2⁻¹ ⬝ H3
end