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CNF_snd_lt {b o : ordinal.{u}} (hb : 1 < b) {x : ordinal × ordinal} : x ∈ CNF b o → x.2 < b
begin refine CNF_rec b _ (λ o ho IH, _) o, { simp }, { rw CNF_ne_zero ho, rintro (rfl | h), { simpa using div_opow_log_lt o hb }, { exact IH h } } end
theorem
ordinal.CNF_snd_lt
set_theory.ordinal
src/set_theory/ordinal/cantor_normal_form.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
Every coefficient in the Cantor normal form `CNF b o` is less than `b`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
CNF_sorted (b o : ordinal) : ((CNF b o).map prod.fst).sorted (>)
begin refine CNF_rec b _ (λ o ho IH, _) o, { simp }, { cases le_or_lt b 1 with hb hb, { simp [CNF_of_le_one hb ho] }, { cases lt_or_le o b with hob hbo, { simp [CNF_of_lt ho hob] }, { rw [CNF_ne_zero ho, list.map_cons, list.sorted_cons], refine ⟨λ a H, _, IH⟩, rw list.mem_map a...
theorem
ordinal.CNF_sorted
set_theory.ordinal
src/set_theory/ordinal/cantor_normal_form.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "list.mem_map", "list.sorted_cons", "ordinal" ]
The exponents of the Cantor normal form are decreasing.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_def (a b : ordinal) : a ^ b = if a = 0 then 1 - b else limit_rec_on b 1 (λ _ IH, IH * a) (λ b _, bsup.{u u} b)
rfl
theorem
ordinal.opow_def
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
zero_opow' (a : ordinal) : 0 ^ a = 1 - a
by simp only [opow_def, if_pos rfl]
theorem
ordinal.zero_opow'
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
zero_opow {a : ordinal} (a0 : a ≠ 0) : 0 ^ a = 0
by rwa [zero_opow', ordinal.sub_eq_zero_iff_le, one_le_iff_ne_zero]
theorem
ordinal.zero_opow
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal", "ordinal.sub_eq_zero_iff_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_zero (a : ordinal) : a ^ 0 = 1
by by_cases a = 0; [simp only [opow_def, if_pos h, sub_zero], simp only [opow_def, if_neg h, limit_rec_on_zero]]
theorem
ordinal.opow_zero
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_succ (a b : ordinal) : a ^ succ b = a ^ b * a
if h : a = 0 then by subst a; simp only [zero_opow (succ_ne_zero _), mul_zero] else by simp only [opow_def, limit_rec_on_succ, if_neg h]
theorem
ordinal.opow_succ
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "mul_zero", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_limit {a b : ordinal} (a0 : a ≠ 0) (h : is_limit b) : a ^ b = bsup.{u u} b (λ c _, a ^ c)
by simp only [opow_def, if_neg a0]; rw limit_rec_on_limit _ _ _ _ h; refl
theorem
ordinal.opow_limit
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_le_of_limit {a b c : ordinal} (a0 : a ≠ 0) (h : is_limit b) : a ^ b ≤ c ↔ ∀ b' < b, a ^ b' ≤ c
by rw [opow_limit a0 h, bsup_le_iff]
theorem
ordinal.opow_le_of_limit
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lt_opow_of_limit {a b c : ordinal} (b0 : b ≠ 0) (h : is_limit c) : a < b ^ c ↔ ∃ c' < c, a < b ^ c'
by rw [← not_iff_not, not_exists]; simp only [not_lt, opow_le_of_limit b0 h, exists_prop, not_and]
theorem
ordinal.lt_opow_of_limit
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "exists_prop", "not_and", "not_exists", "not_iff_not", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_one (a : ordinal) : a ^ 1 = a
by rw [← succ_zero, opow_succ]; simp only [opow_zero, one_mul]
theorem
ordinal.opow_one
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "one_mul", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one_opow (a : ordinal) : 1 ^ a = 1
begin apply limit_rec_on a, { simp only [opow_zero] }, { intros _ ih, simp only [opow_succ, ih, mul_one] }, refine λ b l IH, eq_of_forall_ge_iff (λ c, _), rw [opow_le_of_limit ordinal.one_ne_zero l], exact ⟨λ H, by simpa only [opow_zero] using H 0 l.pos, λ H b' h, by rwa IH _ h⟩, end
theorem
ordinal.one_opow
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "eq_of_forall_ge_iff", "ih", "mul_one", "ordinal", "ordinal.one_ne_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_pos {a : ordinal} (b) (a0 : 0 < a) : 0 < a ^ b
begin have h0 : 0 < a ^ 0, {simp only [opow_zero, zero_lt_one]}, apply limit_rec_on b, { exact h0 }, { intros b IH, rw [opow_succ], exact mul_pos IH a0 }, { exact λ b l _, (lt_opow_of_limit (ordinal.pos_iff_ne_zero.1 a0) l).2 ⟨0, l.pos, h0⟩ }, end
theorem
ordinal.opow_pos
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal", "zero_lt_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_ne_zero {a : ordinal} (b) (a0 : a ≠ 0) : a ^ b ≠ 0
ordinal.pos_iff_ne_zero.1 $ opow_pos b $ ordinal.pos_iff_ne_zero.2 a0
theorem
ordinal.opow_ne_zero
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_is_normal {a : ordinal} (h : 1 < a) : is_normal ((^) a)
have a0 : 0 < a, from zero_lt_one.trans h, ⟨λ b, by simpa only [mul_one, opow_succ] using (mul_lt_mul_iff_left (opow_pos b a0)).2 h, λ b l c, opow_le_of_limit (ne_of_gt a0) l⟩
theorem
ordinal.opow_is_normal
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "mul_lt_mul_iff_left", "mul_one", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_lt_opow_iff_right {a b c : ordinal} (a1 : 1 < a) : a ^ b < a ^ c ↔ b < c
(opow_is_normal a1).lt_iff
theorem
ordinal.opow_lt_opow_iff_right
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_le_opow_iff_right {a b c : ordinal} (a1 : 1 < a) : a ^ b ≤ a ^ c ↔ b ≤ c
(opow_is_normal a1).le_iff
theorem
ordinal.opow_le_opow_iff_right
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_right_inj {a b c : ordinal} (a1 : 1 < a) : a ^ b = a ^ c ↔ b = c
(opow_is_normal a1).inj
theorem
ordinal.opow_right_inj
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_is_limit {a b : ordinal} (a1 : 1 < a) : is_limit b → is_limit (a ^ b)
(opow_is_normal a1).is_limit
theorem
ordinal.opow_is_limit
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_is_limit_left {a b : ordinal} (l : is_limit a) (hb : b ≠ 0) : is_limit (a ^ b)
begin rcases zero_or_succ_or_limit b with e|⟨b,rfl⟩|l', { exact absurd e hb }, { rw opow_succ, exact mul_is_limit (opow_pos _ l.pos) l }, { exact opow_is_limit l.one_lt l' } end
theorem
ordinal.opow_is_limit_left
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_le_opow_right {a b c : ordinal} (h₁ : 0 < a) (h₂ : b ≤ c) : a ^ b ≤ a ^ c
begin cases lt_or_eq_of_le (one_le_iff_pos.2 h₁) with h₁ h₁, { exact (opow_le_opow_iff_right h₁).2 h₂ }, { subst a, simp only [one_opow] } end
theorem
ordinal.opow_le_opow_right
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_le_opow_left {a b : ordinal} (c) (ab : a ≤ b) : a ^ c ≤ b ^ c
begin by_cases a0 : a = 0, { subst a, by_cases c0 : c = 0, { subst c, simp only [opow_zero] }, { simp only [zero_opow c0, ordinal.zero_le] } }, { apply limit_rec_on c, { simp only [opow_zero] }, { intros c IH, simpa only [opow_succ] using mul_le_mul' IH ab }, { exact λ c l IH, (opow_le_of_limi...
theorem
ordinal.opow_le_opow_left
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "mul_le_mul'", "ordinal", "ordinal.zero_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
left_le_opow (a : ordinal) {b : ordinal} (b1 : 0 < b) : a ≤ a ^ b
begin nth_rewrite 0 ←opow_one a, cases le_or_gt a 1 with a1 a1, { cases lt_or_eq_of_le a1 with a0 a1, { rw lt_one_iff_zero at a0, rw [a0, zero_opow ordinal.one_ne_zero], exact ordinal.zero_le _ }, rw [a1, one_opow, one_opow] }, rwa [opow_le_opow_iff_right a1, one_le_iff_pos] end
theorem
ordinal.left_le_opow
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal", "ordinal.one_ne_zero", "ordinal.zero_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
right_le_opow {a : ordinal} (b) (a1 : 1 < a) : b ≤ a ^ b
(opow_is_normal a1).self_le _
theorem
ordinal.right_le_opow
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_lt_opow_left_of_succ {a b c : ordinal} (ab : a < b) : a ^ succ c < b ^ succ c
by { rw [opow_succ, opow_succ], exact (mul_le_mul_right' (opow_le_opow_left c ab.le) a).trans_lt (mul_lt_mul_of_pos_left ab (opow_pos c ((ordinal.zero_le a).trans_lt ab))) }
theorem
ordinal.opow_lt_opow_left_of_succ
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "mul_le_mul_right'", "mul_lt_mul_of_pos_left", "ordinal", "ordinal.zero_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_add (a b c : ordinal) : a ^ (b + c) = a ^ b * a ^ c
begin rcases eq_or_ne a 0 with rfl | a0, { rcases eq_or_ne c 0 with rfl | c0, { simp }, have : b + c ≠ 0 := ((ordinal.pos_iff_ne_zero.2 c0).trans_le (le_add_left _ _)).ne', simp only [zero_opow c0, zero_opow this, mul_zero] }, rcases eq_or_lt_of_le (one_le_iff_ne_zero.2 a0) with rfl | a1, { simp only [o...
theorem
ordinal.opow_add
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "eq_of_forall_ge_iff", "eq_or_lt_of_le", "eq_or_ne", "mul_assoc", "mul_one", "mul_zero", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_one_add (a b : ordinal) : a ^ (1 + b) = a * a ^ b
by rw [opow_add, opow_one]
theorem
ordinal.opow_one_add
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_dvd_opow (a) {b c : ordinal} (h : b ≤ c) : a ^ b ∣ a ^ c
⟨a ^ (c - b), by rw [←opow_add, ordinal.add_sub_cancel_of_le h] ⟩
theorem
ordinal.opow_dvd_opow
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal", "ordinal.add_sub_cancel_of_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_dvd_opow_iff {a b c : ordinal} (a1 : 1 < a) : a ^ b ∣ a ^ c ↔ b ≤ c
⟨λ h, le_of_not_lt $ λ hn, not_le_of_lt ((opow_lt_opow_iff_right a1).2 hn) $ le_of_dvd (opow_ne_zero _ $ one_le_iff_ne_zero.1 $ a1.le) h, opow_dvd_opow _⟩
theorem
ordinal.opow_dvd_opow_iff
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "not_le_of_lt", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_mul (a b c : ordinal) : a ^ (b * c) = (a ^ b) ^ c
begin by_cases b0 : b = 0, {simp only [b0, zero_mul, opow_zero, one_opow]}, by_cases a0 : a = 0, { subst a, by_cases c0 : c = 0, {simp only [c0, mul_zero, opow_zero]}, simp only [zero_opow b0, zero_opow c0, zero_opow (mul_ne_zero b0 c0)] }, cases eq_or_lt_of_le (one_le_iff_ne_zero.2 a0) with a1 a1, { ...
theorem
ordinal.opow_mul
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "eq_of_forall_ge_iff", "eq_or_lt_of_le", "mul_ne_zero", "mul_zero", "ordinal", "zero_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
log (b : ordinal) (x : ordinal) : ordinal
if h : 1 < b then pred (Inf {o | x < b ^ o}) else 0
def
ordinal.log
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
The ordinal logarithm is the solution `u` to the equation `x = b ^ u * v + w` where `v < b` and `w < b ^ u`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
log_nonempty {b x : ordinal} (h : 1 < b) : {o | x < b ^ o}.nonempty
⟨_, succ_le_iff.1 (right_le_opow _ h)⟩
theorem
ordinal.log_nonempty
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
The set in the definition of `log` is nonempty.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
log_def {b : ordinal} (h : 1 < b) (x : ordinal) : log b x = pred (Inf {o | x < b ^ o})
by simp only [log, dif_pos h]
theorem
ordinal.log_def
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
log_of_not_one_lt_left {b : ordinal} (h : ¬ 1 < b) (x : ordinal) : log b x = 0
by simp only [log, dif_neg h]
theorem
ordinal.log_of_not_one_lt_left
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
log_of_left_le_one {b : ordinal} (h : b ≤ 1) : ∀ x, log b x = 0
log_of_not_one_lt_left h.not_lt
theorem
ordinal.log_of_left_le_one
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
log_zero_left : ∀ b, log 0 b = 0
log_of_left_le_one zero_le_one
lemma
ordinal.log_zero_left
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "zero_le_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
log_zero_right (b : ordinal) : log b 0 = 0
if b1 : 1 < b then begin rw [log_def b1, ← ordinal.le_zero, pred_le], apply cInf_le', dsimp, rw [succ_zero, opow_one], exact zero_lt_one.trans b1 end else by simp only [log_of_not_one_lt_left b1]
theorem
ordinal.log_zero_right
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "cInf_le'", "ordinal", "ordinal.le_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
log_one_left : ∀ b, log 1 b = 0
log_of_left_le_one le_rfl
theorem
ordinal.log_one_left
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "le_rfl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
succ_log_def {b x : ordinal} (hb : 1 < b) (hx : x ≠ 0) : succ (log b x) = Inf {o | x < b ^ o}
begin let t := Inf {o | x < b ^ o}, have : x < b ^ t := Inf_mem (log_nonempty hb), rcases zero_or_succ_or_limit t with h|h|h, { refine ((one_le_iff_ne_zero.2 hx).not_lt _).elim, simpa only [h, opow_zero] }, { rw [show log b x = pred t, from log_def hb x, succ_pred_iff_is_succ.2 h] }, { rcases (l...
theorem
ordinal.succ_log_def
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "Inf_mem", "le_cInf_iff''", "le_rfl", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lt_opow_succ_log_self {b : ordinal} (hb : 1 < b) (x : ordinal) : x < b ^ succ (log b x)
begin rcases eq_or_ne x 0 with rfl | hx, { apply opow_pos _ (zero_lt_one.trans hb) }, { rw succ_log_def hb hx, exact Inf_mem (log_nonempty hb) } end
theorem
ordinal.lt_opow_succ_log_self
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "Inf_mem", "eq_or_ne", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_log_le_self (b) {x : ordinal} (hx : x ≠ 0) : b ^ log b x ≤ x
begin rcases eq_or_ne b 0 with rfl | b0, { rw zero_opow', refine (sub_le_self _ _).trans (one_le_iff_ne_zero.2 hx) }, rcases lt_or_eq_of_le (one_le_iff_ne_zero.2 b0) with hb | rfl, { refine le_of_not_lt (λ h, (lt_succ (log b x)).not_le _), have := @cInf_le' _ _ {o | x < b ^ o} _ h, rwa ←succ_log_def...
theorem
ordinal.opow_log_le_self
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "cInf_le'", "eq_or_ne", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_le_iff_le_log {b x c : ordinal} (hb : 1 < b) (hx : x ≠ 0) : b ^ c ≤ x ↔ c ≤ log b x
⟨λ h, le_of_not_lt $ λ hn, (lt_opow_succ_log_self hb x).not_le $ ((opow_le_opow_iff_right hb).2 (succ_le_of_lt hn)).trans h, λ h, ((opow_le_opow_iff_right hb).2 h).trans (opow_log_le_self b hx)⟩
theorem
ordinal.opow_le_iff_le_log
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
`opow b` and `log b` (almost) form a Galois connection.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lt_opow_iff_log_lt {b x c : ordinal} (hb : 1 < b) (hx : x ≠ 0) : x < b ^ c ↔ log b x < c
lt_iff_lt_of_le_iff_le (opow_le_iff_le_log hb hx)
theorem
ordinal.lt_opow_iff_log_lt
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "lt_iff_lt_of_le_iff_le", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
log_pos {b o : ordinal} (hb : 1 < b) (ho : o ≠ 0) (hbo : b ≤ o) : 0 < log b o
by rwa [←succ_le_iff, succ_zero, ←opow_le_iff_le_log hb ho, opow_one]
theorem
ordinal.log_pos
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
log_eq_zero {b o : ordinal} (hbo : o < b) : log b o = 0
begin rcases eq_or_ne o 0 with rfl | ho, { exact log_zero_right b }, cases le_or_lt b 1 with hb hb, { rcases le_one_iff.1 hb with rfl | rfl, { exact log_zero_left o }, { exact log_one_left o } }, { rwa [←ordinal.le_zero, ←lt_succ_iff, succ_zero, ←lt_opow_iff_log_lt hb ho, opow_one] } end
theorem
ordinal.log_eq_zero
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "eq_or_ne", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
log_mono_right (b) {x y : ordinal} (xy : x ≤ y) : log b x ≤ log b y
if hx : x = 0 then by simp only [hx, log_zero_right, ordinal.zero_le] else if hb : 1 < b then (opow_le_iff_le_log hb (lt_of_lt_of_le (ordinal.pos_iff_ne_zero.2 hx) xy).ne').1 $ (opow_log_le_self _ hx).trans xy else by simp only [log_of_not_one_lt_left hb, ordinal.zero_le]
theorem
ordinal.log_mono_right
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal", "ordinal.zero_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
log_le_self (b x : ordinal) : log b x ≤ x
if hx : x = 0 then by simp only [hx, log_zero_right, ordinal.zero_le] else if hb : 1 < b then (right_le_opow _ hb).trans (opow_log_le_self b hx) else by simp only [log_of_not_one_lt_left hb, ordinal.zero_le]
theorem
ordinal.log_le_self
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal", "ordinal.zero_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
log_one_right (b : ordinal) : log b 1 = 0
if hb : 1 < b then log_eq_zero hb else log_of_not_one_lt_left hb 1
theorem
ordinal.log_one_right
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mod_opow_log_lt_self (b : ordinal) {o : ordinal} (ho : o ≠ 0) : o % b ^ log b o < o
begin rcases eq_or_ne b 0 with rfl | hb, { simpa using ordinal.pos_iff_ne_zero.2 ho }, { exact (mod_lt _ $ opow_ne_zero _ hb).trans_le (opow_log_le_self _ ho) } end
theorem
ordinal.mod_opow_log_lt_self
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "eq_or_ne", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
log_mod_opow_log_lt_log_self {b o : ordinal} (hb : 1 < b) (ho : o ≠ 0) (hbo : b ≤ o) : log b (o % b ^ log b o) < log b o
begin cases eq_or_ne (o % b ^ log b o) 0, { rw [h, log_zero_right], apply log_pos hb ho hbo }, { rw [←succ_le_iff, succ_log_def hb h], apply cInf_le', apply mod_lt, rw ←ordinal.pos_iff_ne_zero, exact opow_pos _ (zero_lt_one.trans hb) } end
theorem
ordinal.log_mod_opow_log_lt_log_self
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "cInf_le'", "eq_or_ne", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_mul_add_pos {b v : ordinal} (hb : b ≠ 0) (u) (hv : v ≠ 0) (w) : 0 < b ^ u * v + w
(opow_pos u $ ordinal.pos_iff_ne_zero.2 hb).trans_le $ (le_mul_left _ $ ordinal.pos_iff_ne_zero.2 hv).trans $ le_add_right _ _
lemma
ordinal.opow_mul_add_pos
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "le_mul_left", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_mul_add_lt_opow_mul_succ {b u w : ordinal} (v : ordinal) (hw : w < b ^ u) : b ^ u * v + w < b ^ u * (succ v)
by rwa [mul_succ, add_lt_add_iff_left]
lemma
ordinal.opow_mul_add_lt_opow_mul_succ
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
opow_mul_add_lt_opow_succ {b u v w : ordinal} (hvb : v < b) (hw : w < b ^ u) : b ^ u * v + w < b ^ (succ u)
begin convert (opow_mul_add_lt_opow_mul_succ v hw).trans_le (mul_le_mul_left' (succ_le_of_lt hvb) _), exact opow_succ b u end
lemma
ordinal.opow_mul_add_lt_opow_succ
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "mul_le_mul_left'", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
log_opow_mul_add {b u v w : ordinal} (hb : 1 < b) (hv : v ≠ 0) (hvb : v < b) (hw : w < b ^ u) : log b (b ^ u * v + w) = u
begin have hne' := (opow_mul_add_pos (zero_lt_one.trans hb).ne' u hv w).ne', by_contra' hne, cases lt_or_gt_of_ne hne with h h, { rw ←lt_opow_iff_log_lt hb hne' at h, exact h.not_le ((le_mul_left _ (ordinal.pos_iff_ne_zero.2 hv)).trans (le_add_right _ _)) }, { change _ < _ at h, rw [←succ_le_iff, ←opo...
theorem
ordinal.log_opow_mul_add
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "le_mul_left", "not_lt_of_le", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
log_opow {b : ordinal} (hb : 1 < b) (x : ordinal) : log b (b ^ x) = x
begin convert log_opow_mul_add hb zero_ne_one.symm hb (opow_pos x (zero_lt_one.trans hb)), rw [add_zero, mul_one] end
theorem
ordinal.log_opow
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "mul_one", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_opow_log_pos (b : ordinal) {o : ordinal} (ho : o ≠ 0) : 0 < o / b ^ log b o
begin rcases eq_zero_or_pos b with (rfl | hb), { simpa using ordinal.pos_iff_ne_zero.2 ho }, { rw div_pos (opow_ne_zero _ hb.ne'), exact opow_log_le_self b ho } end
theorem
ordinal.div_opow_log_pos
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "div_pos", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_opow_log_lt {b : ordinal} (o : ordinal) (hb : 1 < b) : o / b ^ log b o < b
begin rw [div_lt (opow_pos _ (zero_lt_one.trans hb)).ne', ←opow_succ], exact lt_opow_succ_log_self hb o end
theorem
ordinal.div_opow_log_lt
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_log_le_log_mul {x y : ordinal} (b : ordinal) (hx : x ≠ 0) (hy : y ≠ 0) : log b x + log b y ≤ log b (x * y)
begin by_cases hb : 1 < b, { rw [←opow_le_iff_le_log hb (mul_ne_zero hx hy), opow_add], exact mul_le_mul' (opow_log_le_self b hx) (opow_log_le_self b hy) }, simp only [log_of_not_one_lt_left hb, zero_add] end
theorem
ordinal.add_log_le_log_mul
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "mul_le_mul'", "mul_ne_zero", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_cast_opow (m : ℕ) : ∀ n : ℕ, ((pow m n : ℕ) : ordinal) = m ^ n
| 0 := by simp | (n+1) := by rw [pow_succ', nat_cast_mul, nat_cast_opow, nat.cast_succ, add_one_eq_succ, opow_succ]
theorem
ordinal.nat_cast_opow
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "nat.cast_succ", "ordinal", "pow_succ'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sup_opow_nat {o : ordinal} (ho : 0 < o) : sup (λ n : ℕ, o ^ n) = o ^ ω
begin rcases lt_or_eq_of_le (one_le_iff_pos.2 ho) with ho₁ | rfl, { exact (opow_is_normal ho₁).apply_omega }, { rw one_opow, refine le_antisymm (sup_le (λ n, by rw one_opow)) _, convert le_sup _ 0, rw [nat.cast_zero, opow_zero] } end
theorem
ordinal.sup_opow_nat
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[ "nat.cast_zero", "ordinal", "sup_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
positivity_opow : expr → tactic strictness
| `(@has_pow.pow _ _ %%inst %%a %%b) := do strictness_a ← core a, match strictness_a with | positive p := positive <$> mk_app ``opow_pos [b, p] | _ := failed -- We already know that `0 ≤ x` for all `x : ordinal` end | _ := failed
def
tactic.positivity_opow
set_theory.ordinal
src/set_theory/ordinal/exponential.lean
[ "set_theory.ordinal.arithmetic" ]
[]
Extension for the `positivity` tactic: `ordinal.opow` takes positive values on positive inputs.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nfp_family (f : ι → ordinal → ordinal) (a) : ordinal
sup (list.foldr f a)
def
ordinal.nfp_family
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
The next common fixed point, at least `a`, for a family of normal functions. This is defined for any family of functions, as the supremum of all values reachable by applying finitely many functions in the family to `a`. `ordinal.nfp_family_fp` shows this is a fixed point, `ordinal.le_nfp_family` shows it's at least `...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nfp_family_eq_sup (f : ι → ordinal → ordinal) (a) : nfp_family f a = sup (list.foldr f a)
rfl
theorem
ordinal.nfp_family_eq_sup
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
foldr_le_nfp_family (f : ι → ordinal → ordinal) (a l) : list.foldr f a l ≤ nfp_family f a
le_sup _ _
theorem
ordinal.foldr_le_nfp_family
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
le_nfp_family (f : ι → ordinal → ordinal) (a) : a ≤ nfp_family f a
le_sup _ []
theorem
ordinal.le_nfp_family
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lt_nfp_family {a b} : a < nfp_family f b ↔ ∃ l, a < list.foldr f b l
lt_sup
theorem
ordinal.lt_nfp_family
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nfp_family_le_iff {a b} : nfp_family f a ≤ b ↔ ∀ l, list.foldr f a l ≤ b
sup_le_iff
theorem
ordinal.nfp_family_le_iff
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "sup_le_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nfp_family_le {a b} : (∀ l, list.foldr f a l ≤ b) → nfp_family f a ≤ b
sup_le
theorem
ordinal.nfp_family_le
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "sup_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nfp_family_monotone (hf : ∀ i, monotone (f i)) : monotone (nfp_family f)
λ a b h, sup_le $ λ l, (list.foldr_monotone hf l h).trans (le_sup _ l)
theorem
ordinal.nfp_family_monotone
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "list.foldr_monotone", "monotone", "sup_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
apply_lt_nfp_family (H : ∀ i, is_normal (f i)) {a b} (hb : b < nfp_family f a) (i) : f i b < nfp_family f a
let ⟨l, hl⟩ := lt_nfp_family.1 hb in lt_sup.2 ⟨i :: l, (H i).strict_mono hl⟩
theorem
ordinal.apply_lt_nfp_family
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "strict_mono" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
apply_lt_nfp_family_iff [nonempty ι] (H : ∀ i, is_normal (f i)) {a b} : (∀ i, f i b < nfp_family f a) ↔ b < nfp_family f a
⟨λ h, lt_nfp_family.2 $ let ⟨l, hl⟩ := lt_sup.1 $ h $ classical.arbitrary ι in ⟨l, ((H _).self_le b).trans_lt hl⟩, apply_lt_nfp_family H⟩
theorem
ordinal.apply_lt_nfp_family_iff
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "classical.arbitrary" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nfp_family_le_apply [nonempty ι] (H : ∀ i, is_normal (f i)) {a b} : (∃ i, nfp_family f a ≤ f i b) ↔ nfp_family f a ≤ b
by { rw ←not_iff_not, push_neg, exact apply_lt_nfp_family_iff H }
theorem
ordinal.nfp_family_le_apply
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nfp_family_le_fp (H : ∀ i, monotone (f i)) {a b} (ab : a ≤ b) (h : ∀ i, f i b ≤ b) : nfp_family f a ≤ b
sup_le $ λ l, begin by_cases hι : is_empty ι, { resetI, rwa unique.eq_default l }, { haveI := not_is_empty_iff.1 hι, induction l with i l IH generalizing a, {exact ab}, exact (H i (IH ab)).trans (h i) } end
theorem
ordinal.nfp_family_le_fp
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "is_empty", "monotone", "sup_le", "unique.eq_default" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nfp_family_fp {i} (H : is_normal (f i)) (a) : f i (nfp_family f a) = nfp_family f a
begin unfold nfp_family, rw @is_normal.sup _ H _ _ ⟨[]⟩, apply le_antisymm; refine ordinal.sup_le (λ l, _), { exact le_sup _ (i :: l) }, { exact (H.self_le _).trans (le_sup _ _) } end
theorem
ordinal.nfp_family_fp
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal.sup_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
apply_le_nfp_family [hι : nonempty ι] {f : ι → ordinal → ordinal} (H : ∀ i, is_normal (f i)) {a b} : (∀ i, f i b ≤ nfp_family f a) ↔ b ≤ nfp_family f a
begin refine ⟨λ h, _, λ h i, _⟩, { unfreezingI { cases hι with i }, exact ((H i).self_le b).trans (h i) }, rw ←nfp_family_fp (H i), exact (H i).monotone h end
theorem
ordinal.apply_le_nfp_family
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "monotone", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nfp_family_eq_self {f : ι → ordinal → ordinal} {a} (h : ∀ i, f i a = a) : nfp_family f a = a
le_antisymm (sup_le $ λ l, by rw list.foldr_fixed' h l) $ le_nfp_family f a
theorem
ordinal.nfp_family_eq_self
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "list.foldr_fixed'", "ordinal", "sup_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fp_family_unbounded (H : ∀ i, is_normal (f i)) : (⋂ i, function.fixed_points (f i)).unbounded (<)
λ a, ⟨_, λ s ⟨i, hi⟩, begin rw ←hi, exact nfp_family_fp (H i) a end, (le_nfp_family f a).not_lt⟩
theorem
ordinal.fp_family_unbounded
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "function.fixed_points" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
deriv_family (f : ι → ordinal → ordinal) (o : ordinal) : ordinal
limit_rec_on o (nfp_family f 0) (λ a IH, nfp_family f (succ IH)) (λ a l, bsup.{(max u v) u} a)
def
ordinal.deriv_family
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
The derivative of a family of normal functions is the sequence of their common fixed points. This is defined for all functions such that `ordinal.deriv_family_zero`, `ordinal.deriv_family_succ`, and `ordinal.deriv_family_limit` are satisfied.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
deriv_family_zero (f : ι → ordinal → ordinal) : deriv_family f 0 = nfp_family f 0
limit_rec_on_zero _ _ _
theorem
ordinal.deriv_family_zero
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
deriv_family_succ (f : ι → ordinal → ordinal) (o) : deriv_family f (succ o) = nfp_family f (succ (deriv_family f o))
limit_rec_on_succ _ _ _ _
theorem
ordinal.deriv_family_succ
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
deriv_family_limit (f : ι → ordinal → ordinal) {o} : is_limit o → deriv_family f o = bsup.{(max u v) u} o (λ a _, deriv_family f a)
limit_rec_on_limit _ _ _ _
theorem
ordinal.deriv_family_limit
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
deriv_family_is_normal (f : ι → ordinal → ordinal) : is_normal (deriv_family f)
⟨λ o, by rw [deriv_family_succ, ← succ_le_iff]; apply le_nfp_family, λ o l a, by rw [deriv_family_limit _ l, bsup_le_iff]⟩
theorem
ordinal.deriv_family_is_normal
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
deriv_family_fp {i} (H : is_normal (f i)) (o : ordinal.{max u v}) : f i (deriv_family f o) = deriv_family f o
begin refine limit_rec_on o _ (λ o IH, _) _, { rw [deriv_family_zero], exact nfp_family_fp H 0 }, { rw [deriv_family_succ], exact nfp_family_fp H _ }, { intros o l IH, rw [deriv_family_limit _ l, is_normal.bsup.{(max u v) u (max u v)} H (λ a _, deriv_family f a) l.1], refine eq_of_forall_ge_iff (λ...
theorem
ordinal.deriv_family_fp
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "eq_of_forall_ge_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
le_iff_deriv_family (H : ∀ i, is_normal (f i)) {a} : (∀ i, f i a ≤ a) ↔ ∃ o, deriv_family f o = a
⟨λ ha, begin suffices : ∀ o (_ : a ≤ deriv_family f o), ∃ o, deriv_family f o = a, from this a ((deriv_family_is_normal _).self_le _), refine λ o, limit_rec_on o (λ h₁, ⟨0, le_antisymm _ h₁⟩) (λ o IH h₁, _) (λ o l IH h₁, _), { rw deriv_family_zero, exact nfp_family_le_fp (λ i, (H i).monotone) (ordinal.zero_...
theorem
ordinal.le_iff_deriv_family
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "eq_or_lt_of_le", "monotone", "not_ball", "ordinal.zero_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fp_iff_deriv_family (H : ∀ i, is_normal (f i)) {a} : (∀ i, f i a = a) ↔ ∃ o, deriv_family f o = a
iff.trans ⟨λ h i, le_of_eq (h i), λ h i, (H i).le_iff_eq.1 (h i)⟩ (le_iff_deriv_family H)
theorem
ordinal.fp_iff_deriv_family
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
deriv_family_eq_enum_ord (H : ∀ i, is_normal (f i)) : deriv_family f = enum_ord (⋂ i, function.fixed_points (f i))
begin rw ←eq_enum_ord _ (fp_family_unbounded H), use (deriv_family_is_normal f).strict_mono, rw set.range_eq_iff, refine ⟨_, λ a ha, _⟩, { rintros a S ⟨i, hi⟩, rw ←hi, exact deriv_family_fp (H i) a }, rw set.mem_Inter at ha, rwa ←fp_iff_deriv_family H end
theorem
ordinal.deriv_family_eq_enum_ord
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "function.fixed_points", "set.mem_Inter", "set.range_eq_iff", "strict_mono" ]
For a family of normal functions, `ordinal.deriv_family` enumerates the common fixed points.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nfp_bfamily (o : ordinal) (f : Π b < o, ordinal → ordinal) : ordinal → ordinal
nfp_family (family_of_bfamily o f)
def
ordinal.nfp_bfamily
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
The next common fixed point, at least `a`, for a family of normal functions indexed by ordinals. This is defined as `ordinal.nfp_family` of the type-indexed family associated to `f`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nfp_bfamily_eq_nfp_family {o : ordinal} (f : Π b < o, ordinal → ordinal) : nfp_bfamily o f = nfp_family (family_of_bfamily o f)
rfl
theorem
ordinal.nfp_bfamily_eq_nfp_family
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
foldr_le_nfp_bfamily {o : ordinal} (f : Π b < o, ordinal → ordinal) (a l) : list.foldr (family_of_bfamily o f) a l ≤ nfp_bfamily o f a
le_sup _ _
theorem
ordinal.foldr_le_nfp_bfamily
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
le_nfp_bfamily {o : ordinal} (f : Π b < o, ordinal → ordinal) (a) : a ≤ nfp_bfamily o f a
le_sup _ []
theorem
ordinal.le_nfp_bfamily
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lt_nfp_bfamily {a b} : a < nfp_bfamily o f b ↔ ∃ l, a < list.foldr (family_of_bfamily o f) b l
lt_sup
theorem
ordinal.lt_nfp_bfamily
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nfp_bfamily_le_iff {o : ordinal} {f : Π b < o, ordinal → ordinal} {a b} : nfp_bfamily o f a ≤ b ↔ ∀ l, list.foldr (family_of_bfamily o f) a l ≤ b
sup_le_iff
theorem
ordinal.nfp_bfamily_le_iff
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal", "sup_le_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nfp_bfamily_le {o : ordinal} {f : Π b < o, ordinal → ordinal} {a b} : (∀ l, list.foldr (family_of_bfamily o f) a l ≤ b) → nfp_bfamily o f a ≤ b
sup_le
theorem
ordinal.nfp_bfamily_le
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal", "sup_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nfp_bfamily_monotone (hf : ∀ i hi, monotone (f i hi)) : monotone (nfp_bfamily o f)
nfp_family_monotone (λ i, hf _ _)
theorem
ordinal.nfp_bfamily_monotone
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "monotone" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
apply_lt_nfp_bfamily (H : ∀ i hi, is_normal (f i hi)) {a b} (hb : b < nfp_bfamily o f a) (i hi) : f i hi b < nfp_bfamily o f a
begin rw ←family_of_bfamily_enum o f, apply apply_lt_nfp_family _ hb, exact λ _, H _ _ end
theorem
ordinal.apply_lt_nfp_bfamily
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
apply_lt_nfp_bfamily_iff (ho : o ≠ 0) (H : ∀ i hi, is_normal (f i hi)) {a b} : (∀ i hi, f i hi b < nfp_bfamily o f a) ↔ b < nfp_bfamily o f a
⟨λ h, begin haveI := out_nonempty_iff_ne_zero.2 ho, refine (apply_lt_nfp_family_iff _).1 (λ _, h _ _), exact λ _, H _ _, end, apply_lt_nfp_bfamily H⟩
theorem
ordinal.apply_lt_nfp_bfamily_iff
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nfp_bfamily_le_apply (ho : o ≠ 0) (H : ∀ i hi, is_normal (f i hi)) {a b} : (∃ i hi, nfp_bfamily o f a ≤ f i hi b) ↔ nfp_bfamily o f a ≤ b
by { rw ←not_iff_not, push_neg, convert apply_lt_nfp_bfamily_iff ho H, simp only [not_le] }
theorem
ordinal.nfp_bfamily_le_apply
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nfp_bfamily_le_fp (H : ∀ i hi, monotone (f i hi)) {a b} (ab : a ≤ b) (h : ∀ i hi, f i hi b ≤ b) : nfp_bfamily o f a ≤ b
nfp_family_le_fp (λ _, H _ _) ab (λ i, h _ _)
theorem
ordinal.nfp_bfamily_le_fp
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "monotone" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nfp_bfamily_fp {i hi} (H : is_normal (f i hi)) (a) : f i hi (nfp_bfamily o f a) = nfp_bfamily o f a
by { rw ←family_of_bfamily_enum o f, apply nfp_family_fp, rw family_of_bfamily_enum, exact H }
theorem
ordinal.nfp_bfamily_fp
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
apply_le_nfp_bfamily (ho : o ≠ 0) (H : ∀ i hi, is_normal (f i hi)) {a b} : (∀ i hi, f i hi b ≤ nfp_bfamily o f a) ↔ b ≤ nfp_bfamily o f a
begin refine ⟨λ h, _, λ h i hi, _⟩, { have ho' : 0 < o := ordinal.pos_iff_ne_zero.2 ho, exact ((H 0 ho').self_le b).trans (h 0 ho') }, { rw ←nfp_bfamily_fp (H i hi), exact (H i hi).monotone h } end
theorem
ordinal.apply_le_nfp_bfamily
set_theory.ordinal
src/set_theory/ordinal/fixed_point.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "monotone" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83