fix: Update examples to work with latest Lean nightly#107
fix: Update examples to work with latest Lean nightly#107david-christiansen wants to merge 1 commit intomasterfrom
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| have feq : f (choose ex) = f a := choose_spec ex | ||
| calc linv f (f a) | ||
| _ = choose ex := dif_pos ex | ||
| _ = choose ex := by simp |
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This fixes an error where dif_pos's implicit arguments were not being found (namely the Decidable instance and the else branch). This lemma is really designed to be used with simp rather than directly, and simp solves the goal.
| #check Proof -- Proof : Prop → Type | ||
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| axiom and_comm (p q : Prop) : Proof (Implies (And p q) (And q p)) | ||
| axiom and_commutative (p q : Prop) : Proof (Implies (And p q) (And q p)) |
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We now have and_comm in scope by default. I chose to rename it here, rather than secretly stick it in a namespace, because I want code bits to work if people type them in.
On the other hand, the hidden Proof structure is not present, so this is a very weak argument for this solution. Happy to do the other one if you'd prefer.
| calc | ||
| x ∣ y := h₁ | ||
| _ = z := h₂ | ||
| _ ∣ 2*z := divides_mul .. |
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This notation is now built-in, and they were conflicting. It didn't seem to be worth a longer aside in the text to save this, so I deleted it.
| def Divides (x y : Nat) : Prop := | ||
| ∃ k, k*x = y | ||
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| def divides_trans (h₁ : divides x y) (h₂ : divides y z) : divides x z := | ||
| def Divides_trans (h₁ : Divides x y) (h₂ : Divides y z) : Divides x z := | ||
| let ⟨k₁, d₁⟩ := h₁ | ||
| let ⟨k₂, d₂⟩ := h₂ | ||
| ⟨k₁ * k₂, by rw [Nat.mul_comm k₁ k₂, Nat.mul_assoc, d₁, d₂]⟩ | ||
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| def divides_mul (x : Nat) (k : Nat) : divides x (k*x) := | ||
| def Divides_mul (x : Nat) (k : Nat) : Divides x (k*x) := | ||
| ⟨k, rfl⟩ | ||
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| instance : Trans divides divides divides where | ||
| trans := divides_trans | ||
| instance : Trans Divides Divides Divides where | ||
| trans := Divides_trans | ||
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| example (h₁ : divides x y) (h₂ : y = z) : divides x (2*z) := | ||
| example (h₁ : Divides x y) (h₂ : y = z) : Divides x (2*z) := | ||
| calc | ||
| divides x y := h₁ | ||
| Divides x y := h₁ | ||
| _ = z := h₂ | ||
| divides _ (2*z) := divides_mul .. | ||
| Divides _ (2*z) := Divides_mul .. |
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This is just a rename to more closely follow Lean 4 conventions while I was here
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@avigad - I believe you're the right one to approve these changes. If not, let me know, and I'll start working down the list of co-authors. Thanks! |
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These changes allow the tests to pass with the latest Lean nightly again.