chore: fix typos
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3 changed files with 4 additions and 4 deletions
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@ -60,7 +60,7 @@ end BasicFunctions
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```lean
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-- Lean has first-class functions.
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-- `twice` takes two argumes `f` and `a` where
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-- `twice` takes two arguments `f` and `a` where
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-- `f` is a function from natural numbers to natural numbers, and
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-- `a` is a natural number.
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def twice (f : Nat → Nat) (a : Nat) :=
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@ -114,7 +114,7 @@ constant α : Type _
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#check α
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```
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Several Lean 3 users use the shorhand `Type*` for `Type _`. The `Type*` notation is not builtin in Lean 4, but you can be easily define it using a `macro`.
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Several Lean 3 users use the shorhand `Type*` for `Type _`. The `Type*` notation is not builtin in Lean 4, but you can easily define it using a `macro`.
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```lean
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macro "Type*" : term => `(Type _)
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@ -15,7 +15,7 @@ class Coe (α : Sort u) (β : Sort v) where
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class CoeTC (α : Sort u) (β : Sort v) where
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coe : α → β
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/- Expensive coercion that can only appear at the beggining of a sequence of coercions. -/
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/- Expensive coercion that can only appear at the beginning of a sequence of coercions. -/
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class CoeHead (α : Sort u) (β : Sort v) where
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coe : α → β
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@ -115,7 +115,7 @@ instance subtypeCoe {α : Sort u} {p : α → Prop} : CoeHead { x // p x } α wh
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/-
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Remark: one may question why we use `OfNat α` instead of `Coe Nat α`.
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Reason: `OfNat` is for implementing polymorphic numeric literals, and we may
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want to have numberic literals for a type α and **no** coercion from `Nat` to `α`. -/
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want to have numeric literals for a type α and **no** coercion from `Nat` to `α`. -/
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instance hasOfNatOfCoe [Coe α β] [OfNat α n] : OfNat β n where
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ofNat := coe (OfNat.ofNat n : α)
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