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https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.nestedIntervalSeq_isCauSeq
[214, 1]
[222, 28]
intro ε ε0
ι : Type U : ι → Set ℝ ⊢ IsCauSeq abs (nestedIntervalSeq U)
ι : Type U : ι → Set ℝ ε : ℝ ε0 : ε > 0 ⊢ ∃ i, ∀ j ≥ i, |nestedIntervalSeq U j - nestedIntervalSeq U i| < ε
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.nestedIntervalSeq_isCauSeq
[214, 1]
[222, 28]
have ⟨i, hi⟩ : ∃ i : ℕ, ε⁻¹ < 2 ^ i := pow_unbounded_of_one_lt ε⁻¹ (by linarith)
ι : Type U : ι → Set ℝ ε : ℝ ε0 : ε > 0 ⊢ ∃ i, ∀ j ≥ i, |nestedIntervalSeq U j - nestedIntervalSeq U i| < ε
ι : Type U : ι → Set ℝ ε : ℝ ε0 : ε > 0 i : ℕ hi : ε⁻¹ < 2 ^ i ⊢ ∃ i, ∀ j ≥ i, |nestedIntervalSeq U j - nestedIntervalSeq U i| < ε
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.nestedIntervalSeq_isCauSeq
[214, 1]
[222, 28]
have hi : (2 ^ i : ℝ)⁻¹ < ε := inv_lt_of_inv_lt ε0 hi
ι : Type U : ι → Set ℝ ε : ℝ ε0 : ε > 0 i : ℕ hi : ε⁻¹ < 2 ^ i ⊢ ∃ i, ∀ j ≥ i, |nestedIntervalSeq U j - nestedIntervalSeq U i| < ε
ι : Type U : ι → Set ℝ ε : ℝ ε0 : ε > 0 i : ℕ hi✝ : ε⁻¹ < 2 ^ i hi : (2 ^ i)⁻¹ < ε ⊢ ∃ i, ∀ j ≥ i, |nestedIntervalSeq U j - nestedIntervalSeq U i| < ε
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.nestedIntervalSeq_isCauSeq
[214, 1]
[222, 28]
exists i
ι : Type U : ι → Set ℝ ε : ℝ ε0 : ε > 0 i : ℕ hi✝ : ε⁻¹ < 2 ^ i hi : (2 ^ i)⁻¹ < ε ⊢ ∃ i, ∀ j ≥ i, |nestedIntervalSeq U j - nestedIntervalSeq U i| < ε
ι : Type U : ι → Set ℝ ε : ℝ ε0 : ε > 0 i : ℕ hi✝ : ε⁻¹ < 2 ^ i hi : (2 ^ i)⁻¹ < ε ⊢ ∀ j ≥ i, |nestedIntervalSeq U j - nestedIntervalSeq U i| < ε
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.nestedIntervalSeq_isCauSeq
[214, 1]
[222, 28]
intro j hj
ι : Type U : ι → Set ℝ ε : ℝ ε0 : ε > 0 i : ℕ hi✝ : ε⁻¹ < 2 ^ i hi : (2 ^ i)⁻¹ < ε ⊢ ∀ j ≥ i, |nestedIntervalSeq U j - nestedIntervalSeq U i| < ε
ι : Type U : ι → Set ℝ ε : ℝ ε0 : ε > 0 i : ℕ hi✝ : ε⁻¹ < 2 ^ i hi : (2 ^ i)⁻¹ < ε j : ℕ hj : j ≥ i ⊢ |nestedIntervalSeq U j - nestedIntervalSeq U i| < ε
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.nestedIntervalSeq_isCauSeq
[214, 1]
[222, 28]
calc |nestedIntervalSeq U j - nestedIntervalSeq U i| _ ≤ (2 ^ i : ℝ)⁻¹ := nestedIntervalSeq_isCauSeq_aux' U hj _ < ε := hi
ι : Type U : ι → Set ℝ ε : ℝ ε0 : ε > 0 i : ℕ hi✝ : ε⁻¹ < 2 ^ i hi : (2 ^ i)⁻¹ < ε j : ℕ hj : j ≥ i ⊢ |nestedIntervalSeq U j - nestedIntervalSeq U i| < ε
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.nestedIntervalSeq_isCauSeq
[214, 1]
[222, 28]
linarith
ι : Type U : ι → Set ℝ ε : ℝ ε0 : ε > 0 ⊢ 1 < 2
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.nestedIntervalSeq_tendsto
[232, 1]
[234, 47]
apply (nestedIntervalCauSeq U).tendsto_limit
ι : Type U : ι → Set ℝ ⊢ Tendsto (nestedIntervalSeq U) atTop (𝓝 (CauSeq.lim (nestedIntervalCauSeq U)))
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
by_contra H
ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i ⊢ HasFinSubCover U (Icc 0 1)
ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) ⊢ False
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
set c := (nestedIntervalCauSeq U).lim
ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) ⊢ False
ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) ⊢ False
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
rcases cover (nestedIntervalLim_mem U 0) with ⟨_, ⟨i, rfl⟩, hU' : c ∈ U i⟩
ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) ⊢ False
case intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ⊢ False
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
rcases Metric.isOpen_iff.mp (hU i) c hU' with ⟨ε, ε0, hε⟩
case intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ⊢ False
case intro.intro.intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i ⊢ False
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
have ⟨n, hn⟩ : ∃ n : ℕ, (ε / 2)⁻¹ < 2 ^ n := by apply pow_unbounded_of_one_lt (ε / 2)⁻¹ (by linarith)
case intro.intro.intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i ⊢ False
case intro.intro.intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn : (ε / 2)⁻¹ < 2 ^ n ⊢ False
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
suffices HasFinSubCover U I(n) by apply nestedInterval_not_HasFinSubCover H n this
case intro.intro.intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn : (ε / 2)⁻¹ < 2 ^ n ⊢ False
case intro.intro.intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn : (ε / 2)⁻¹ < 2 ^ n ⊢ HasFinSubCover U (Icc (nestedInterval U n).1 (nestedInterval U n).2)
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
suffices I(n) ⊆ U i by exists {i} simpa using this
case intro.intro.intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn : (ε / 2)⁻¹ < 2 ^ n ⊢ HasFinSubCover U (Icc (nestedInterval U n).1 (nestedInterval U n).2)
case intro.intro.intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn : (ε / 2)⁻¹ < 2 ^ n ⊢ Icc (nestedInterval U n).1 (nestedInterval U n).2 ⊆ U i
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
suffices ∀ x, x ∈ I(n) → |x - c| < ε by intro x hx apply hε (this x hx)
case intro.intro.intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn : (ε / 2)⁻¹ < 2 ^ n ⊢ Icc (nestedInterval U n).1 (nestedInterval U n).2 ⊆ U i
case intro.intro.intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn : (ε / 2)⁻¹ < 2 ^ n ⊢ ∀ x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2, |x - c| < ε
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
intro x hx
case intro.intro.intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn : (ε / 2)⁻¹ < 2 ^ n ⊢ ∀ x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2, |x - c| < ε
case intro.intro.intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn : (ε / 2)⁻¹ < 2 ^ n x : ℝ hx : x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2 ⊢ |x - c| < ε
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
have hba : β n - α n = (2 ^ n : ℝ)⁻¹ := nestedInterval_len U n
case intro.intro.intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn : (ε / 2)⁻¹ < 2 ^ n x : ℝ hx : x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2 ⊢ |x - c| < ε
case intro.intro.intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn : (ε / 2)⁻¹ < 2 ^ n x : ℝ hx : x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2 hba : (nestedInterval U n).2 - (nestedInterval U n).1 = (2 ^ n)⁻¹ ⊢ |x - c| < ε
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
have hn := inv_lt_of_inv_lt (by linarith) hn
case intro.intro.intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn : (ε / 2)⁻¹ < 2 ^ n x : ℝ hx : x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2 hba : (nestedInterval U n).2 - (nestedInterval U n).1 = (2 ^ n)⁻¹ ⊢ |x - c| < ε
case intro.intro.intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn✝ : (ε / 2)⁻¹ < 2 ^ n x : ℝ hx : x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2 hba : (nestedInterval U n).2 - (nestedInterval U n).1 = (2 ^ n)⁻¹ hn : (2 ^ n)⁻¹ < ε / 2 ⊢ |x - c| < ε
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
have hc : α n ≤ c ∧ c ≤ β n := nestedIntervalLim_mem U n
case intro.intro.intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn✝ : (ε / 2)⁻¹ < 2 ^ n x : ℝ hx : x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2 hba : (nestedInterval U n).2 - (nestedInterval U n).1 = (2 ^ n)⁻¹ hn : (2 ^ n)⁻¹ < ε / 2 ⊢ |x - c| < ε
case intro.intro.intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn✝ : (ε / 2)⁻¹ < 2 ^ n x : ℝ hx : x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2 hba : (nestedInterval U n).2 - (nestedInterval U n).1 = (2 ^ n)⁻¹ hn : (2 ^ n)⁻¹ < ε / 2 hc : (nestedInterval U n).1 ≤ c ∧ c ≤ (nestedInterval U n).2 ⊢ |x - c| < ε
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
have hx : α n ≤ x ∧ x ≤ β n := hx
case intro.intro.intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn✝ : (ε / 2)⁻¹ < 2 ^ n x : ℝ hx : x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2 hba : (nestedInterval U n).2 - (nestedInterval U n).1 = (2 ^ n)⁻¹ hn : (2 ^ n)⁻¹ < ε / 2 hc : (nestedInterval U n).1 ≤ c ∧ c ≤ (nestedInterval U n).2 ⊢ |x - c| < ε
case intro.intro.intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn✝ : (ε / 2)⁻¹ < 2 ^ n x : ℝ hx✝ : x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2 hba : (nestedInterval U n).2 - (nestedInterval U n).1 = (2 ^ n)⁻¹ hn : (2 ^ n)⁻¹ < ε / 2 hc : (nestedInterval U n).1 ≤ c ∧ c ≤ (nestedInterval U n).2 hx : (nestedInterval U n).1 ≤ x ∧ x ≤ (nestedInterval U n).2 ⊢ |x - c| < ε
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
calc |x - c| _ = |(x - α n) - (c - α n)| := by simp _ ≤ |x - α n| + |c - α n| := by apply abs_sub _ = (x - α n) + (c - α n) := by apply congrArg₂ <;> rw [abs_eq_self] <;> linarith _ < ε / 2 + ε / 2 := by linarith _ = ε := by ring
case intro.intro.intro.intro.intro ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn✝ : (ε / 2)⁻¹ < 2 ^ n x : ℝ hx✝ : x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2 hba : (nestedInterval U n).2 - (nestedInterval U n).1 = (2 ^ n)⁻¹ hn : (2 ^ n)⁻¹ < ε / 2 hc : (nestedInterval U n).1 ≤ c ∧ c ≤ (nestedInterval U n).2 hx : (nestedInterval U n).1 ≤ x ∧ x ≤ (nestedInterval U n).2 ⊢ |x - c| < ε
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
apply pow_unbounded_of_one_lt (ε / 2)⁻¹ (by linarith)
ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i ⊢ ∃ n, (ε / 2)⁻¹ < 2 ^ n
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
linarith
ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i ⊢ 1 < 2
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
apply nestedInterval_not_HasFinSubCover H n this
ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn : (ε / 2)⁻¹ < 2 ^ n this : HasFinSubCover U (Icc (nestedInterval U n).1 (nestedInterval U n).2) ⊢ False
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
exists {i}
ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn : (ε / 2)⁻¹ < 2 ^ n this : Icc (nestedInterval U n).1 (nestedInterval U n).2 ⊆ U i ⊢ HasFinSubCover U (Icc (nestedInterval U n).1 (nestedInterval U n).2)
ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn : (ε / 2)⁻¹ < 2 ^ n this : Icc (nestedInterval U n).1 (nestedInterval U n).2 ⊆ U i ⊢ Icc (nestedInterval U n).1 (nestedInterval U n).2 ⊆ ⋃ i_1 ∈ {i}, U i_1
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
simpa using this
ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn : (ε / 2)⁻¹ < 2 ^ n this : Icc (nestedInterval U n).1 (nestedInterval U n).2 ⊆ U i ⊢ Icc (nestedInterval U n).1 (nestedInterval U n).2 ⊆ ⋃ i_1 ∈ {i}, U i_1
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
intro x hx
ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn : (ε / 2)⁻¹ < 2 ^ n this : ∀ x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2, |x - c| < ε ⊢ Icc (nestedInterval U n).1 (nestedInterval U n).2 ⊆ U i
ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn : (ε / 2)⁻¹ < 2 ^ n this : ∀ x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2, |x - c| < ε x : ℝ hx : x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2 ⊢ x ∈ U i
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
apply hε (this x hx)
ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn : (ε / 2)⁻¹ < 2 ^ n this : ∀ x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2, |x - c| < ε x : ℝ hx : x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2 ⊢ x ∈ U i
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
linarith
ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn : (ε / 2)⁻¹ < 2 ^ n x : ℝ hx : x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2 hba : (nestedInterval U n).2 - (nestedInterval U n).1 = (2 ^ n)⁻¹ ⊢ 0 < ε / 2
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
simp
ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn✝ : (ε / 2)⁻¹ < 2 ^ n x : ℝ hx✝ : x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2 hba : (nestedInterval U n).2 - (nestedInterval U n).1 = (2 ^ n)⁻¹ hn : (2 ^ n)⁻¹ < ε / 2 hc : (nestedInterval U n).1 ≤ c ∧ c ≤ (nestedInterval U n).2 hx : (nestedInterval U n).1 ≤ x ∧ x ≤ (nestedInterval U n).2 ⊢ |x - c| = |x - (nestedInterval U n).1 - (c - (nestedInterval U n).1)|
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
apply abs_sub
ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn✝ : (ε / 2)⁻¹ < 2 ^ n x : ℝ hx✝ : x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2 hba : (nestedInterval U n).2 - (nestedInterval U n).1 = (2 ^ n)⁻¹ hn : (2 ^ n)⁻¹ < ε / 2 hc : (nestedInterval U n).1 ≤ c ∧ c ≤ (nestedInterval U n).2 hx : (nestedInterval U n).1 ≤ x ∧ x ≤ (nestedInterval U n).2 ⊢ |x - (nestedInterval U n).1 - (c - (nestedInterval U n).1)| ≤ |x - (nestedInterval U n).1| + |c - (nestedInterval U n).1|
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
apply congrArg₂ <;> rw [abs_eq_self] <;> linarith
ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn✝ : (ε / 2)⁻¹ < 2 ^ n x : ℝ hx✝ : x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2 hba : (nestedInterval U n).2 - (nestedInterval U n).1 = (2 ^ n)⁻¹ hn : (2 ^ n)⁻¹ < ε / 2 hc : (nestedInterval U n).1 ≤ c ∧ c ≤ (nestedInterval U n).2 hx : (nestedInterval U n).1 ≤ x ∧ x ≤ (nestedInterval U n).2 ⊢ |x - (nestedInterval U n).1| + |c - (nestedInterval U n).1| = x - (nestedInterval U n).1 + (c - (nestedInterval U n).1)
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
linarith
ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn✝ : (ε / 2)⁻¹ < 2 ^ n x : ℝ hx✝ : x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2 hba : (nestedInterval U n).2 - (nestedInterval U n).1 = (2 ^ n)⁻¹ hn : (2 ^ n)⁻¹ < ε / 2 hc : (nestedInterval U n).1 ≤ c ∧ c ≤ (nestedInterval U n).2 hx : (nestedInterval U n).1 ≤ x ∧ x ≤ (nestedInterval U n).2 ⊢ x - (nestedInterval U n).1 + (c - (nestedInterval U n).1) < ε / 2 + ε / 2
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Analysis/Lecture3.lean
Tutorial.HasFinSubCover_of_Icc
[254, 1]
[291, 21]
ring
ι : Type U : ι → Set ℝ hU : ∀ (i : ι), IsOpen (U i) cover : Icc 0 1 ⊆ ⋃ i, U i H : ¬HasFinSubCover U (Icc 0 1) c : ℝ := CauSeq.lim (nestedIntervalCauSeq U) i : ι hU' : c ∈ U i ε : ℝ ε0 : ε > 0 hε : Metric.ball c ε ⊆ U i n : ℕ hn✝ : (ε / 2)⁻¹ < 2 ^ n x : ℝ hx✝ : x ∈ Icc (nestedInterval U n).1 (nestedInterval U n).2 hba : (nestedInterval U n).2 - (nestedInterval U n).1 = (2 ^ n)⁻¹ hn : (2 ^ n)⁻¹ < ε / 2 hc : (nestedInterval U n).1 ≤ c ∧ c ≤ (nestedInterval U n).2 hx : (nestedInterval U n).1 ≤ x ∧ x ≤ (nestedInterval U n).2 ⊢ ε / 2 + ε / 2 = ε
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Tutorial/Advanced/Category/Lecture2.lean
Tutorial.Category.Initial.uniq'
[28, 1]
[30, 25]
sorry
C : Type u inst✝ : Category C a : C h : Initial a b : C f g : Hom a b ⊢ f = h.fromInitial b
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Tutorial/Advanced/Category/Lecture2.lean
Tutorial.Category.Initial.uniq'
[28, 1]
[30, 25]
sorry
C : Type u inst✝ : Category C a : C h : Initial a b : C f g : Hom a b ⊢ h.fromInitial b = g
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Tutorial/Advanced/Category/Lecture2.lean
Tutorial.Coequalizer.hom_id
[309, 1]
[309, 71]
cases i <;> rfl
J : Type u₁ inst✝¹ : Category J C : Type u₂ inst✝ : Category C F : Functor J C i : Shape ⊢ ShapeHom.id i = 𝟙 i
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Injective.comp
[38, 1]
[48, 11]
rw [Injective]
X Y Z : Type f : X → Y g : Y → Z hfinj : Injective f hginj : Injective g ⊢ Injective (g ∘ f)
X Y Z : Type f : X → Y g : Y → Z hfinj : Injective f hginj : Injective g ⊢ ∀ {x₁ x₂ : X}, (g ∘ f) x₁ = (g ∘ f) x₂ → x₁ = x₂
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Injective.comp
[38, 1]
[48, 11]
intro x₁ x₂ hgf
X Y Z : Type f : X → Y g : Y → Z hfinj : Injective f hginj : Injective g ⊢ ∀ {x₁ x₂ : X}, (g ∘ f) x₁ = (g ∘ f) x₂ → x₁ = x₂
X Y Z : Type f : X → Y g : Y → Z hfinj : Injective f hginj : Injective g x₁ x₂ : X hgf : (g ∘ f) x₁ = (g ∘ f) x₂ ⊢ x₁ = x₂
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Injective.comp
[38, 1]
[48, 11]
have hf := hginj hgf
X Y Z : Type f : X → Y g : Y → Z hfinj : Injective f hginj : Injective g x₁ x₂ : X hgf : (g ∘ f) x₁ = (g ∘ f) x₂ ⊢ x₁ = x₂
X Y Z : Type f : X → Y g : Y → Z hfinj : Injective f hginj : Injective g x₁ x₂ : X hgf : (g ∘ f) x₁ = (g ∘ f) x₂ hf : f x₁ = f x₂ ⊢ x₁ = x₂
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Injective.comp
[38, 1]
[48, 11]
apply hfinj
X Y Z : Type f : X → Y g : Y → Z hfinj : Injective f hginj : Injective g x₁ x₂ : X hgf : (g ∘ f) x₁ = (g ∘ f) x₂ hf : f x₁ = f x₂ ⊢ x₁ = x₂
case a X Y Z : Type f : X → Y g : Y → Z hfinj : Injective f hginj : Injective g x₁ x₂ : X hgf : (g ∘ f) x₁ = (g ∘ f) x₂ hf : f x₁ = f x₂ ⊢ f x₁ = f x₂
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Injective.comp
[38, 1]
[48, 11]
apply hf
case a X Y Z : Type f : X → Y g : Y → Z hfinj : Injective f hginj : Injective g x₁ x₂ : X hgf : (g ∘ f) x₁ = (g ∘ f) x₂ hf : f x₁ = f x₂ ⊢ f x₁ = f x₂
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Injective.of_comp
[78, 1]
[89, 10]
rw [Injective]
X Y Z : Type f : X → Y g : Y → Z hgfinj : Injective (g ∘ f) ⊢ Injective f
X Y Z : Type f : X → Y g : Y → Z hgfinj : Injective (g ∘ f) ⊢ ∀ {x₁ x₂ : X}, f x₁ = f x₂ → x₁ = x₂
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Injective.of_comp
[78, 1]
[89, 10]
intro x₁ x₂ hf
X Y Z : Type f : X → Y g : Y → Z hgfinj : Injective (g ∘ f) ⊢ ∀ {x₁ x₂ : X}, f x₁ = f x₂ → x₁ = x₂
X Y Z : Type f : X → Y g : Y → Z hgfinj : Injective (g ∘ f) x₁ x₂ : X hf : f x₁ = f x₂ ⊢ x₁ = x₂
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Injective.of_comp
[78, 1]
[89, 10]
have h : g (f x₁) = g (f x₂) := by rw [hf]
X Y Z : Type f : X → Y g : Y → Z hgfinj : Injective (g ∘ f) x₁ x₂ : X hf : f x₁ = f x₂ ⊢ x₁ = x₂
X Y Z : Type f : X → Y g : Y → Z hgfinj : Injective (g ∘ f) x₁ x₂ : X hf : f x₁ = f x₂ h : g (f x₁) = g (f x₂) ⊢ x₁ = x₂
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Injective.of_comp
[78, 1]
[89, 10]
apply hgfinj
X Y Z : Type f : X → Y g : Y → Z hgfinj : Injective (g ∘ f) x₁ x₂ : X hf : f x₁ = f x₂ h : g (f x₁) = g (f x₂) ⊢ x₁ = x₂
case a X Y Z : Type f : X → Y g : Y → Z hgfinj : Injective (g ∘ f) x₁ x₂ : X hf : f x₁ = f x₂ h : g (f x₁) = g (f x₂) ⊢ (g ∘ f) x₁ = (g ∘ f) x₂
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Injective.of_comp
[78, 1]
[89, 10]
simp
case a X Y Z : Type f : X → Y g : Y → Z hgfinj : Injective (g ∘ f) x₁ x₂ : X hf : f x₁ = f x₂ h : g (f x₁) = g (f x₂) ⊢ (g ∘ f) x₁ = (g ∘ f) x₂
case a X Y Z : Type f : X → Y g : Y → Z hgfinj : Injective (g ∘ f) x₁ x₂ : X hf : f x₁ = f x₂ h : g (f x₁) = g (f x₂) ⊢ g (f x₁) = g (f x₂)
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Injective.of_comp
[78, 1]
[89, 10]
apply h
case a X Y Z : Type f : X → Y g : Y → Z hgfinj : Injective (g ∘ f) x₁ x₂ : X hf : f x₁ = f x₂ h : g (f x₁) = g (f x₂) ⊢ g (f x₁) = g (f x₂)
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Injective.of_comp
[78, 1]
[89, 10]
rw [hf]
X Y Z : Type f : X → Y g : Y → Z hgfinj : Injective (g ∘ f) x₁ x₂ : X hf : f x₁ = f x₂ ⊢ g (f x₁) = g (f x₂)
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Surjective.comp
[137, 1]
[148, 14]
rw [Surjective]
X Y Z : Type f : X → Y g : Y → Z hfsurj : Surjective f hgsurj : Surjective g ⊢ Surjective (g ∘ f)
X Y Z : Type f : X → Y g : Y → Z hfsurj : Surjective f hgsurj : Surjective g ⊢ ∀ (y : Z), ∃ x, (g ∘ f) x = y
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Surjective.comp
[137, 1]
[148, 14]
intro z
X Y Z : Type f : X → Y g : Y → Z hfsurj : Surjective f hgsurj : Surjective g ⊢ ∀ (y : Z), ∃ x, (g ∘ f) x = y
X Y Z : Type f : X → Y g : Y → Z hfsurj : Surjective f hgsurj : Surjective g z : Z ⊢ ∃ x, (g ∘ f) x = z
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Surjective.comp
[137, 1]
[148, 14]
have ⟨y, hy⟩ := hgsurj z
X Y Z : Type f : X → Y g : Y → Z hfsurj : Surjective f hgsurj : Surjective g z : Z ⊢ ∃ x, (g ∘ f) x = z
X Y Z : Type f : X → Y g : Y → Z hfsurj : Surjective f hgsurj : Surjective g z : Z y : Y hy : g y = z ⊢ ∃ x, (g ∘ f) x = z
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Surjective.comp
[137, 1]
[148, 14]
have ⟨x, hx⟩ := hfsurj y
X Y Z : Type f : X → Y g : Y → Z hfsurj : Surjective f hgsurj : Surjective g z : Z y : Y hy : g y = z ⊢ ∃ x, (g ∘ f) x = z
X Y Z : Type f : X → Y g : Y → Z hfsurj : Surjective f hgsurj : Surjective g z : Z y : Y hy : g y = z x : X hx : f x = y ⊢ ∃ x, (g ∘ f) x = z
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Surjective.comp
[137, 1]
[148, 14]
exists x
X Y Z : Type f : X → Y g : Y → Z hfsurj : Surjective f hgsurj : Surjective g z : Z y : Y hy : g y = z x : X hx : f x = y ⊢ ∃ x, (g ∘ f) x = z
X Y Z : Type f : X → Y g : Y → Z hfsurj : Surjective f hgsurj : Surjective g z : Z y : Y hy : g y = z x : X hx : f x = y ⊢ (g ∘ f) x = z
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Surjective.comp
[137, 1]
[148, 14]
simp
X Y Z : Type f : X → Y g : Y → Z hfsurj : Surjective f hgsurj : Surjective g z : Z y : Y hy : g y = z x : X hx : f x = y ⊢ (g ∘ f) x = z
X Y Z : Type f : X → Y g : Y → Z hfsurj : Surjective f hgsurj : Surjective g z : Z y : Y hy : g y = z x : X hx : f x = y ⊢ g (f x) = z
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Surjective.comp
[137, 1]
[148, 14]
rw [hx, hy]
X Y Z : Type f : X → Y g : Y → Z hfsurj : Surjective f hgsurj : Surjective g z : Z y : Y hy : g y = z x : X hx : f x = y ⊢ g (f x) = z
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Surjective.of_comp
[160, 1]
[164, 13]
intro z
X Y Z : Type f : X → Y g : Y → Z h : Surjective (g ∘ f) ⊢ Surjective g
X Y Z : Type f : X → Y g : Y → Z h : Surjective (g ∘ f) z : Z ⊢ ∃ x, g x = z
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Surjective.of_comp
[160, 1]
[164, 13]
have ⟨x, hx⟩ := h z
X Y Z : Type f : X → Y g : Y → Z h : Surjective (g ∘ f) z : Z ⊢ ∃ x, g x = z
X Y Z : Type f : X → Y g : Y → Z h : Surjective (g ∘ f) z : Z x : X hx : (g ∘ f) x = z ⊢ ∃ x, g x = z
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Basic/Lecture4.lean
Tutorial.Surjective.of_comp
[160, 1]
[164, 13]
exists f x
X Y Z : Type f : X → Y g : Y → Z h : Surjective (g ∘ f) z : Z x : X hx : (g ∘ f) x = z ⊢ ∃ x, g x = z
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.map_one
[45, 1]
[51, 28]
have h : f 1 * f 1 = f 1 * 1 := by rw [← map_mul, mul_one, mul_one]
G₁ G₂ : Type inst✝¹ : Group G₁ inst✝ : Group G₂ f : G₁ →* G₂ ⊢ f 1 = 1
G₁ G₂ : Type inst✝¹ : Group G₁ inst✝ : Group G₂ f : G₁ →* G₂ h : f 1 * f 1 = f 1 * 1 ⊢ f 1 = 1
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.map_one
[45, 1]
[51, 28]
exact mul_left_cancel _ h
G₁ G₂ : Type inst✝¹ : Group G₁ inst✝ : Group G₂ f : G₁ →* G₂ h : f 1 * f 1 = f 1 * 1 ⊢ f 1 = 1
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.map_one
[45, 1]
[51, 28]
rw [← map_mul, mul_one, mul_one]
G₁ G₂ : Type inst✝¹ : Group G₁ inst✝ : Group G₂ f : G₁ →* G₂ ⊢ f 1 * f 1 = f 1 * 1
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.map_inv
[57, 1]
[60, 40]
apply eq_inv_of_mul_eq_one_left
G₁ G₂ : Type inst✝¹ : Group G₁ inst✝ : Group G₂ f : G₁ →* G₂ a : G₁ ⊢ f a⁻¹ = (f a)⁻¹
case a G₁ G₂ : Type inst✝¹ : Group G₁ inst✝ : Group G₂ f : G₁ →* G₂ a : G₁ ⊢ f a⁻¹ * f a = 1
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.map_inv
[57, 1]
[60, 40]
rw [← map_mul, inv_mul_self, map_one]
case a G₁ G₂ : Type inst✝¹ : Group G₁ inst✝ : Group G₂ f : G₁ →* G₂ a : G₁ ⊢ f a⁻¹ * f a = 1
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.injective_iff_map_eq_one
[219, 1]
[230, 31]
constructor
G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ ⊢ Function.Injective ⇑f ↔ ∀ (a : G₁), f a = 1 → a = 1
case mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ ⊢ Function.Injective ⇑f → ∀ (a : G₁), f a = 1 → a = 1 case mpr G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ ⊢ (∀ (a : G₁), f a = 1 → a = 1) → Function.Injective ⇑f
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.injective_iff_map_eq_one
[219, 1]
[230, 31]
intro hf a ha
case mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ ⊢ Function.Injective ⇑f → ∀ (a : G₁), f a = 1 → a = 1
case mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ hf : Function.Injective ⇑f a : G₁ ha : f a = 1 ⊢ a = 1
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.injective_iff_map_eq_one
[219, 1]
[230, 31]
apply hf
case mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ hf : Function.Injective ⇑f a : G₁ ha : f a = 1 ⊢ a = 1
case mp.a G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ hf : Function.Injective ⇑f a : G₁ ha : f a = 1 ⊢ f a = f 1
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.injective_iff_map_eq_one
[219, 1]
[230, 31]
rw [ha, map_one]
case mp.a G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ hf : Function.Injective ⇑f a : G₁ ha : f a = 1 ⊢ f a = f 1
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.injective_iff_map_eq_one
[219, 1]
[230, 31]
intro h a b hab
case mpr G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ ⊢ (∀ (a : G₁), f a = 1 → a = 1) → Function.Injective ⇑f
case mpr G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 a b : G₁ hab : f a = f b ⊢ a = b
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.injective_iff_map_eq_one
[219, 1]
[230, 31]
rw [← mul_inv_eq_one] at *
case mpr G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 a b : G₁ hab : f a = f b ⊢ a = b
case mpr G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 a b : G₁ hab : f a * (f b)⁻¹ = 1 ⊢ a * b⁻¹ = 1
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.injective_iff_map_eq_one
[219, 1]
[230, 31]
apply h
case mpr G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 a b : G₁ hab : f a * (f b)⁻¹ = 1 ⊢ a * b⁻¹ = 1
case mpr.a G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 a b : G₁ hab : f a * (f b)⁻¹ = 1 ⊢ f (a * b⁻¹) = 1
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.injective_iff_map_eq_one
[219, 1]
[230, 31]
rw [map_mul, map_inv, hab]
case mpr.a G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 a b : G₁ hab : f a * (f b)⁻¹ = 1 ⊢ f (a * b⁻¹) = 1
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.ker_eq_bot
[236, 1]
[253, 23]
rw [injective_iff_map_eq_one]
G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ ⊢ ker f = ⊥ ↔ Function.Injective ⇑f
G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ ⊢ ker f = ⊥ ↔ ∀ (a : G₁), f a = 1 → a = 1
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.ker_eq_bot
[236, 1]
[253, 23]
constructor
G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ ⊢ ker f = ⊥ ↔ ∀ (a : G₁), f a = 1 → a = 1
case mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ ⊢ ker f = ⊥ → ∀ (a : G₁), f a = 1 → a = 1 case mpr G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ ⊢ (∀ (a : G₁), f a = 1 → a = 1) → ker f = ⊥
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.ker_eq_bot
[236, 1]
[253, 23]
intro h a (hf : a ∈ f.ker)
case mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ ⊢ ker f = ⊥ → ∀ (a : G₁), f a = 1 → a = 1
case mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ker f = ⊥ a : G₁ hf : a ∈ ker f ⊢ a = 1
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.ker_eq_bot
[236, 1]
[253, 23]
simpa [h] using hf
case mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ker f = ⊥ a : G₁ hf : a ∈ ker f ⊢ a = 1
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.ker_eq_bot
[236, 1]
[253, 23]
intro h
case mpr G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ ⊢ (∀ (a : G₁), f a = 1 → a = 1) → ker f = ⊥
case mpr G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 ⊢ ker f = ⊥
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.ker_eq_bot
[236, 1]
[253, 23]
ext a
case mpr G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 ⊢ ker f = ⊥
case mpr.a G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 a : G₁ ⊢ a ∈ ker f ↔ a ∈ ⊥
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.ker_eq_bot
[236, 1]
[253, 23]
simp only [mem_ker, mem_bot]
case mpr.a G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 a : G₁ ⊢ a ∈ ker f ↔ a ∈ ⊥
case mpr.a G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 a : G₁ ⊢ f a = 1 ↔ a = 1
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.ker_eq_bot
[236, 1]
[253, 23]
constructor
case mpr.a G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 a : G₁ ⊢ f a = 1 ↔ a = 1
case mpr.a.mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 a : G₁ ⊢ f a = 1 → a = 1 case mpr.a.mpr G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 a : G₁ ⊢ a = 1 → f a = 1
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.ker_eq_bot
[236, 1]
[253, 23]
intro ha
case mpr.a.mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 a : G₁ ⊢ f a = 1 → a = 1
case mpr.a.mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 a : G₁ ha : f a = 1 ⊢ a = 1
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.ker_eq_bot
[236, 1]
[253, 23]
apply h
case mpr.a.mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 a : G₁ ha : f a = 1 ⊢ a = 1
case mpr.a.mp.a G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 a : G₁ ha : f a = 1 ⊢ f a = 1
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.ker_eq_bot
[236, 1]
[253, 23]
apply ha
case mpr.a.mp.a G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 a : G₁ ha : f a = 1 ⊢ f a = 1
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.ker_eq_bot
[236, 1]
[253, 23]
intro ha
case mpr.a.mpr G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 a : G₁ ⊢ a = 1 → f a = 1
case mpr.a.mpr G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 a : G₁ ha : a = 1 ⊢ f a = 1
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.ker_eq_bot
[236, 1]
[253, 23]
rw [ha, map_one]
case mpr.a.mpr G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ h : ∀ (a : G₁), f a = 1 → a = 1 a : G₁ ha : a = 1 ⊢ f a = 1
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.range_eq_top
[257, 1]
[273, 18]
constructor
G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ ⊢ range f = ⊤ ↔ Function.Surjective ⇑f
case mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ ⊢ range f = ⊤ → Function.Surjective ⇑f case mpr G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ ⊢ Function.Surjective ⇑f → range f = ⊤
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.range_eq_top
[257, 1]
[273, 18]
intro hrange y
case mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ ⊢ range f = ⊤ → Function.Surjective ⇑f
case mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ hrange : range f = ⊤ y : G₂ ⊢ ∃ a, f a = y
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.range_eq_top
[257, 1]
[273, 18]
have hy : y ∈ (⊤ : Subgroup G₂) := by simp
case mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ hrange : range f = ⊤ y : G₂ ⊢ ∃ a, f a = y
case mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ hrange : range f = ⊤ y : G₂ hy : y ∈ ⊤ ⊢ ∃ a, f a = y
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.range_eq_top
[257, 1]
[273, 18]
rw [← hrange] at hy
case mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ hrange : range f = ⊤ y : G₂ hy : y ∈ ⊤ ⊢ ∃ a, f a = y
case mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ hrange : range f = ⊤ y : G₂ hy : y ∈ range f ⊢ ∃ a, f a = y
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.range_eq_top
[257, 1]
[273, 18]
have ⟨x, hx⟩ := hy
case mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ hrange : range f = ⊤ y : G₂ hy : y ∈ range f ⊢ ∃ a, f a = y
case mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ hrange : range f = ⊤ y : G₂ hy : y ∈ range f x : G₁ hx : f x = y ⊢ ∃ a, f a = y
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.range_eq_top
[257, 1]
[273, 18]
exists x
case mp G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ hrange : range f = ⊤ y : G₂ hy : y ∈ range f x : G₁ hx : f x = y ⊢ ∃ a, f a = y
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.range_eq_top
[257, 1]
[273, 18]
simp
G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ hrange : range f = ⊤ y : G₂ ⊢ y ∈ ⊤
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.range_eq_top
[257, 1]
[273, 18]
intro hsurj
case mpr G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ ⊢ Function.Surjective ⇑f → range f = ⊤
case mpr G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ hsurj : Function.Surjective ⇑f ⊢ range f = ⊤
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.range_eq_top
[257, 1]
[273, 18]
ext y
case mpr G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ hsurj : Function.Surjective ⇑f ⊢ range f = ⊤
case mpr.a G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ hsurj : Function.Surjective ⇑f y : G₂ ⊢ y ∈ range f ↔ y ∈ ⊤
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.range_eq_top
[257, 1]
[273, 18]
simp only [mem_range, mem_top, iff_true]
case mpr.a G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ hsurj : Function.Surjective ⇑f y : G₂ ⊢ y ∈ range f ↔ y ∈ ⊤
case mpr.a G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ hsurj : Function.Surjective ⇑f y : G₂ ⊢ ∃ a, f a = y
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.GroupHom.range_eq_top
[257, 1]
[273, 18]
apply hsurj y
case mpr.a G₁ G₂ G : Type inst✝² : Group G₁ inst✝¹ : Group G₂ inst✝ : Group G f : G₁ →* G₂ hsurj : Function.Surjective ⇑f y : G₂ ⊢ ∃ a, f a = y
no goals
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.homToPerm_injective
[346, 1]
[360, 15]
rw [injective_iff_map_eq_one]
G : Type inst✝ : Group G ⊢ Function.Injective ⇑(homToPerm G)
G : Type inst✝ : Group G ⊢ ∀ (a : G), (homToPerm G) a = 1 → a = 1
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.homToPerm_injective
[346, 1]
[360, 15]
intro a h
G : Type inst✝ : Group G ⊢ ∀ (a : G), (homToPerm G) a = 1 → a = 1
G : Type inst✝ : Group G a : G h : (homToPerm G) a = 1 ⊢ a = 1
https://github.com/yuma-mizuno/lean-math-workshop.git
4a69b0130b276b45212e2b12b90032b146b56d67
Solution/Advanced/Algebra/Lecture2.lean
Tutorial.homToPerm_injective
[346, 1]
[360, 15]
calc a = a * 1 := by simp _ = (homToPerm G a) 1 := by rfl _ = 1 := by simp [h]
G : Type inst✝ : Group G a : G h : (homToPerm G) a = 1 ⊢ a = 1
no goals