lean2/tests/lean/tst11.lean
Leonardo de Moura 4ba097a141 feat(frontends/lean): use lowercase commands, replace 'endscope' and 'endnamespace' with 'end'
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2014-01-05 13:06:36 -08:00

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definition xor (x y : Bool) : Bool := (not x) = y
infixr 50 ⊕ : xor
print xor true false
eval xor true true
eval xor true false
variable a : Bool
print a ⊕ a ⊕ a
check @Subst
theorem EM2 (a : Bool) : a \/ (not a) :=
Case (fun x : Bool, x \/ (not x)) Trivial Trivial a
check EM2
check EM2 a