137 lines
5.4 KiB
Text
137 lines
5.4 KiB
Text
/- A computation of the cohomology groups of K(ℤ,2) using the Serre spectral sequence
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Author: Floris van Doorn-/
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import .serre
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open eq spectrum EM EM.ops int pointed cohomology left_module algebra group fiber is_equiv equiv
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prod is_trunc function
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namespace temp
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definition uH0_circle : uH^0[circle] ≃g gℤ :=
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sorry
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definition uH1_circle : uH^1[circle] ≃g gℤ :=
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sorry
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definition uH_circle_of_ge (n : ℤ) (h : n ≥ 2) : uH^n[circle] ≃g trivial_ab_group :=
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sorry
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definition f : unit → K agℤ 2 :=
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λx, pt
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definition fserre :
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(λn s, uoH^-(n-s)[K agℤ 2, H^-s[circle₊]]) ⟹ᵍ (λn, H^-n[unit₊]) :=
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proof
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converges_to_g_isomorphism
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(serre_convergence_map_of_is_conn pt f (EM_spectrum agℤ) 0
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(is_strunc_EM_spectrum agℤ) (is_conn_EM agℤ 2))
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begin
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intro n s, apply unreduced_ordinary_cohomology_isomorphism_right,
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apply unreduced_cohomology_isomorphism, symmetry,
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refine !fiber_const_equiv ⬝e _,
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refine loop_EM _ 1 ⬝e _,
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exact EM_pequiv_circle
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end
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begin intro n, reflexivity end
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qed
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section
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local notation `X` := converges_to.X fserre
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local notation `E∞` := convergence_theorem.Einf (converges_to.HH fserre)
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local notation `E∞d` := convergence_theorem.Einfdiag (converges_to.HH fserre)
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local notation `E` := exact_couple.E X
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definition fbuilt (n : ℤ) :
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is_built_from (LeftModule_int_of_AbGroup (H^-n[unit₊])) (E∞d (n, 0)) :=
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is_built_from_of_converges_to fserre n
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definition fEinf0 : E∞ (0, 0) ≃lm LeftModule_int_of_AbGroup agℤ :=
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isomorphism_zero_of_is_built_from (fbuilt 0) (by reflexivity) ⬝lm
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lm_iso_int.mk (cohomology_change_int _ _ neg_zero ⬝g
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cohomology_isomorphism pbool_pequiv_add_point_unit _ _ ⬝g ordinary_cohomology_pbool _)
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definition fEinfd (n : ℤ) (m : ℕ) (p : n ≠ 0) : is_contr (E∞d (n, 0) m) :=
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have p' : -n ≠ 0, from λH, p (eq_zero_of_neg_eq_zero H),
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is_contr_quotients (fbuilt n) (@(is_trunc_equiv_closed_rev -2
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(group.equiv_of_isomorphism (cohomology_isomorphism pbool_pequiv_add_point_unit _ _)))
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(EM_dimension' _ _ p')) _
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definition fEinf (n : ℤ) (m : ℕ) (p : n ≠ 0) : is_contr (E∞ (n, -m)) :=
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transport (is_contr ∘ E∞)
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begin
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induction m with m q, reflexivity, refine ap (deg (exact_couple.i X)) q ⬝ _,
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exact prod_eq idp (neg_add m 1)⁻¹
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end
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(fEinfd n m p)
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definition is_contr_fD (n s : ℤ) (p : s > 0) : is_contr (E (n, s)) :=
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have is_contr H^-s[circle₊], from
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is_contr_ordinary_cohomology_of_neg _ _ (neg_neg_of_pos p),
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have is_contr (uoH^-(n-s)[K agℤ 2, H^-s[circle₊]]), from
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is_contr_unreduced_ordinary_cohomology _ _ _ _,
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@(is_contr_equiv_closed (left_module.equiv_of_isomorphism (converges_to.e fserre (n, s))⁻¹ˡᵐ))
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this
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definition is_contr_fD2 (n s : ℤ) (p : n > s) : is_contr (E (n, s)) :=
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have -(n-s) < 0, from neg_neg_of_pos (sub_pos_of_lt p),
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@(is_contr_equiv_closed (left_module.equiv_of_isomorphism (converges_to.e fserre (n, s))⁻¹ˡᵐ))
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(is_contr_ordinary_cohomology_of_neg _ _ this)
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definition is_contr_fD3 (n s : ℤ) (p : s ≤ - 2) : is_contr (E (n, s)) :=
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have -s ≥ 2, from sorry, --from neg_neg_of_pos (sub_pos_of_lt p),
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@(is_contr_equiv_closed (group.equiv_of_isomorphism (unreduced_ordinary_cohomology_isomorphism_right _ (uH_circle_of_ge _ this)⁻¹ᵍ _) ⬝e
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left_module.equiv_of_isomorphism (converges_to.e fserre (n, s))⁻¹ˡᵐ))
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(is_contr_ordinary_cohomology _ _ _ !is_contr_unit)
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--(unreduced_ordinary_cohomology_isomorphism_right _ _ _)
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--(is_contr_ordinary_cohomology_of_neg _ _ this)
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--(is_contr_ordinary_cohomology_of_neg _ _ this)
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definition fE00 : E (0,0) ≃lm LeftModule_int_of_AbGroup agℤ :=
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begin
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refine (Einf_isomorphism fserre 0 _ _)⁻¹ˡᵐ ⬝lm fEinf0,
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intro r H, apply is_contr_fD2, exact sub_nat_lt 0 (r+1),
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intro r H, apply is_contr_fD, change 0 + (r + 1) >[ℤ] 0,
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apply of_nat_lt_of_nat_of_lt,
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apply nat.zero_lt_succ,
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end
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definition Ex0 (n : ℕ) : AddGroup_of_AddAbGroup (E (-n,0)) ≃g uH^n[K agℤ 2] :=
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begin
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refine group_isomorphism_of_lm_isomorphism_int (converges_to.e fserre (-n,0)) ⬝g _,
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refine cohomology_change_int _ _ (ap neg !sub_zero ⬝ !neg_neg) ⬝g
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unreduced_ordinary_cohomology_isomorphism_right _ uH0_circle _,
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end
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definition Ex1 (n : ℕ) : AddGroup_of_AddAbGroup (E (-(n+1),- 1)) ≃g uH^n[K agℤ 2] :=
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begin
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refine group_isomorphism_of_lm_isomorphism_int (converges_to.e fserre (-(n+1),- 1)) ⬝g _,
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refine cohomology_change_int _ _ (ap neg _ ⬝ !neg_neg) ⬝g
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unreduced_ordinary_cohomology_isomorphism_right _ !uH1_circle _,
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exact ap (λx, x - - 1) !neg_add ⬝ !add_sub_cancel
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end
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definition uH0 : uH^0[K agℤ 2] ≃g gℤ :=
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(Ex0 0)⁻¹ᵍ ⬝g group_isomorphism_of_lm_isomorphism_int fE00
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definition fE10 : is_contr (E (- 1,0)) :=
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begin
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refine @(is_trunc_equiv_closed _ _) (fEinf (- 1) 0 dec_star),
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apply equiv_of_isomorphism,
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refine Einf_isomorphism fserre 0 _ _,
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intro r H, exact sorry, exact sorry --apply is_contr_fD2, change (- 1) - (- 1) >[ℤ] (- 0) - (r + 1),
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-- apply is_contr_fD, change (-0) - (r + 1) >[ℤ] 0,
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--exact sub_nat_lt 0 r,
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-- intro r H, apply is_contr_fD, change 0 + (r + 1) >[ℤ] 0,
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-- apply of_nat_lt_of_nat_of_lt,
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-- apply nat.zero_lt_succ,
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end
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definition uH1 : is_contr (uH^1[K agℤ 2]) :=
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begin
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refine @(is_trunc_equiv_closed -2 (group.equiv_of_isomorphism !Ex0)) fE10,
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end
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end
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end temp
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