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fix(doc): correct two more mistakes

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- fix a mistake in code example
- fix singular/plural confusion
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Théo Zimmermann 2015-07-30 18:52:56 +02:00 committed by Leonardo de Moura
parent 3598a6610f
commit 923d12553e
1 changed files with 2 additions and 2 deletions
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doc/lean/tutorial.org
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@ -639,12 +639,12 @@ equality are all dependent functions.
The universal quantifier is just a dependent function. The universal quantifier is just a dependent function.
In Lean, if we have a family of types =B : A → Prop=, In Lean, if we have a family of types =B : A → Prop=,
then =∀ x : A, B a= has type =Prop=. then =∀ a : A, B a= has type =Prop=.
This feature complicates the Lean set-theoretic model, but it This feature complicates the Lean set-theoretic model, but it
improves usability. improves usability.
Several theorem provers have a =forall elimination= (aka Several theorem provers have a =forall elimination= (aka
instantiation) proof rule. instantiation) proof rule.
In Lean (and other systems based on proposition as types), this rule In Lean (and other systems based on propositions as types), this rule
is just function application. is just function application.
In the following example we add an axiom stating that =f x= is =0= In the following example we add an axiom stating that =f x= is =0=
forall =x=. forall =x=.