refactor(library/data/set/*): rename setext to ext
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3 changed files with 8 additions and 8 deletions
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@ -134,7 +134,7 @@ by apply (to_finset_eq_of_to_set_eq !finset.to_set_upto)
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theorem finite_powerset (s : set A) [fins : finite s] : finite (𝒫 s) :=
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theorem finite_powerset (s : set A) [fins : finite s] : finite (𝒫 s) :=
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assert H : (𝒫 s) = finset.to_set '[finset.to_set (#finset 𝒫 (to_finset s))],
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assert H : (𝒫 s) = finset.to_set '[finset.to_set (#finset 𝒫 (to_finset s))],
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from setext (take t, iff.intro
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from ext (take t, iff.intro
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(suppose t ∈ 𝒫 s,
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(suppose t ∈ 𝒫 s,
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assert t ⊆ s, from this,
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assert t ⊆ s, from this,
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assert finite t, from finite_subset this,
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assert finite t, from finite_subset this,
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@ -22,7 +22,7 @@ notation f `'[`:max a `]` := image f a
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theorem image_eq_image_of_eq_on {f1 f2 : X → Y} {a : set X} (H1 : eq_on f1 f2 a) :
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theorem image_eq_image_of_eq_on {f1 f2 : X → Y} {a : set X} (H1 : eq_on f1 f2 a) :
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f1 '[a] = f2 '[a] :=
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f1 '[a] = f2 '[a] :=
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setext (take y, iff.intro
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ext (take y, iff.intro
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(assume H2,
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(assume H2,
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obtain x (H3 : x ∈ a ∧ f1 x = y), from H2,
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obtain x (H3 : x ∈ a ∧ f1 x = y), from H2,
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have H4 : x ∈ a, from and.left H3,
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have H4 : x ∈ a, from and.left H3,
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@ -42,7 +42,7 @@ theorem mem_image_of_mem (f : X → Y) {x : X} {a : set X} (H : x ∈ a) : f x
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mem_image H rfl
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mem_image H rfl
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lemma image_compose (f : Y → Z) (g : X → Y) (a : set X) : (f ∘ g) '[a] = f '[g '[a]] :=
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lemma image_compose (f : Y → Z) (g : X → Y) (a : set X) : (f ∘ g) '[a] = f '[g '[a]] :=
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setext (take z,
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ext (take z,
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iff.intro
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iff.intro
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(assume Hz : z ∈ (f ∘ g) '[a],
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(assume Hz : z ∈ (f ∘ g) '[a],
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obtain x (Hx₁ : x ∈ a) (Hx₂ : f (g x) = z), from Hz,
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obtain x (Hx₁ : x ∈ a) (Hx₂ : f (g x) = z), from Hz,
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@ -60,7 +60,7 @@ mem_image (H Hx₁) Hx₂
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theorem image_union (f : X → Y) (s t : set X) :
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theorem image_union (f : X → Y) (s t : set X) :
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image f (s ∪ t) = image f s ∪ image f t :=
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image f (s ∪ t) = image f s ∪ image f t :=
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setext (take y, iff.intro
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ext (take y, iff.intro
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(assume H : y ∈ image f (s ∪ t),
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(assume H : y ∈ image f (s ∪ t),
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obtain x [(xst : x ∈ s ∪ t) (fxy : f x = y)], from H,
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obtain x [(xst : x ∈ s ∪ t) (fxy : f x = y)], from H,
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or.elim xst
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or.elim xst
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@ -84,7 +84,7 @@ lemma lmul_inj_on (a : A) (H : set A) : inj_on (lmul_by a) H :=
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inj_on_of_left_inv_on (lmul_inv_on a H)
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inj_on_of_left_inv_on (lmul_inv_on a H)
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lemma glcoset_eq_lcoset a (H : set A) : a ∘> H = coset.l a H :=
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lemma glcoset_eq_lcoset a (H : set A) : a ∘> H = coset.l a H :=
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setext
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ext
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begin
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begin
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intro x,
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intro x,
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rewrite [↑glcoset, ↑coset.l, ↑image, ↑set_of, ↑mem, ↑coset.lmul],
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rewrite [↑glcoset, ↑coset.l, ↑image, ↑set_of, ↑mem, ↑coset.lmul],
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@ -103,7 +103,7 @@ lemma glcoset_eq_lcoset a (H : set A) : a ∘> H = coset.l a H :=
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lemma grcoset_eq_rcoset a (H : set A) : H <∘ a = coset.r a H :=
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lemma grcoset_eq_rcoset a (H : set A) : H <∘ a = coset.r a H :=
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begin
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begin
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rewrite [↑grcoset, ↑coset.r, ↑image, ↑coset.rmul, ↑set_of],
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rewrite [↑grcoset, ↑coset.r, ↑image, ↑coset.rmul, ↑set_of],
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apply setext, rewrite ↑mem,
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apply ext, rewrite ↑mem,
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intro x,
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intro x,
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apply iff.intro,
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apply iff.intro,
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show H (x * a⁻¹) → (∃ (x_1 : A), H x_1 ∧ x_1 * a = x), from
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show H (x * a⁻¹) → (∃ (x_1 : A), H x_1 ∧ x_1 * a = x), from
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@ -215,14 +215,14 @@ lemma subgroup_coset_id : ∀ a, a ∈ H → (a ∘> H = H ∧ H <∘ a = H) :=
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assert Pr : H <∘ a ⊆ H, from closed_rcontract a H subg_mul_closed PHa,
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assert Pr : H <∘ a ⊆ H, from closed_rcontract a H subg_mul_closed PHa,
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assert PHainv : H a⁻¹, from subg_has_inv a PHa,
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assert PHainv : H a⁻¹, from subg_has_inv a PHa,
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and.intro
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and.intro
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(setext (assume x,
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(ext (assume x,
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begin
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begin
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esimp [glcoset, mem],
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esimp [glcoset, mem],
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apply iff.intro,
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apply iff.intro,
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apply Pl,
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apply Pl,
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intro PHx, exact (subg_mul_closed a⁻¹ x PHainv PHx)
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intro PHx, exact (subg_mul_closed a⁻¹ x PHainv PHx)
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end))
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end))
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(setext (assume x,
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(ext (assume x,
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begin
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begin
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esimp [grcoset, mem],
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esimp [grcoset, mem],
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apply iff.intro,
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apply iff.intro,
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