lean2/tests/lean/run/cody1.lean
Leonardo de Moura bbff564a1c feat(frontends/lean): persistent notation in sections
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2014-09-06 11:14:20 -07:00

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Text

import logic
abbreviation subsets (P : Type) := P → Prop.
context
hypothesis A : Type.
hypothesis r : A → subsets A.
hypothesis i : subsets A → A.
hypothesis retract {P : subsets A} {a : A} : r (i P) a = P a.
definition delta (a:A) : Prop := ¬ (r a a).
notation `δ` := delta.
-- Crashes unifier!
theorem false_aux : ¬ (δ (i delta))
:= assume H : δ (i delta),
have H' : r (i delta) (i delta),
from eq.rec H (eq.symm retract),
H H'.
end