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add_swap_covariant_class_le : covariant_class ordinal.{u} ordinal.{u} (swap (+)) (≤)
⟨λ c a b h, begin revert h c, exact ( induction_on a $ λ α₁ r₁ hr₁, induction_on b $ λ α₂ r₂ hr₂ ⟨⟨⟨f, fo⟩, fi⟩⟩ c, induction_on c $ λ β s hs, by exactI @rel_embedding.ordinal_type_le _ _ (sum.lex r₁ s) (sum.lex r₂ s) _ _ ⟨f.sum_map (embedding.refl _), λ a b, begin split; intro H, { cases a with a a; ...
instance
ordinal.add_swap_covariant_class_le
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "covariant_class", "rel_embedding.ordinal_type_le", "sum.lex" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
le_add_right (a b : ordinal) : a ≤ a + b
by simpa only [add_zero] using add_le_add_left (ordinal.zero_le b) a
theorem
ordinal.le_add_right
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal", "ordinal.zero_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
le_add_left (a b : ordinal) : a ≤ b + a
by simpa only [zero_add] using add_le_add_right (ordinal.zero_le b) a
theorem
ordinal.le_add_left
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal", "ordinal.zero_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
max_zero_left : ∀ a : ordinal, max 0 a = a
max_bot_left
lemma
ordinal.max_zero_left
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "max_bot_left", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
max_zero_right : ∀ a : ordinal, max a 0 = a
max_bot_right
lemma
ordinal.max_zero_right
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "max_bot_right", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
max_eq_zero {a b : ordinal} : max a b = 0 ↔ a = 0 ∧ b = 0
max_eq_bot
lemma
ordinal.max_eq_zero
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "max_eq_bot", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
Inf_empty : Inf (∅ : set ordinal) = 0
dif_neg not_nonempty_empty
theorem
ordinal.Inf_empty
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "Inf_empty", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
succ_le_iff' {a b : ordinal} : a + 1 ≤ b ↔ a < b
⟨lt_of_lt_of_le (induction_on a $ λ α r _, ⟨⟨⟨⟨λ x, sum.inl x, λ _ _, sum.inl.inj⟩, λ _ _, sum.lex_inl_inl⟩, sum.inr punit.star, λ b, sum.rec_on b (λ x, ⟨λ _, ⟨x, rfl⟩, λ _, sum.lex.sep _ _⟩) (λ x, sum.lex_inr_inr.trans ⟨false.elim, λ ⟨x, H⟩, sum.inl_ne_inr H⟩)⟩⟩), induction_on a $ λ α r hr, induction_on b ...
theorem
ordinal.succ_le_iff'
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal", "principal_seg.init", "rel_embedding.of_monotone", "sum.inl_ne_inr", "sum.lex_inl_inl", "sum.lex_inr_inl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_one_eq_succ (o : ordinal) : o + 1 = succ o
rfl
theorem
ordinal.add_one_eq_succ
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
succ_zero : succ (0 : ordinal) = 1
zero_add 1
theorem
ordinal.succ_zero
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
succ_one : succ (1 : ordinal) = 2
rfl
theorem
ordinal.succ_one
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_succ (o₁ o₂ : ordinal) : o₁ + succ o₂ = succ (o₁ + o₂)
(add_assoc _ _ _).symm
theorem
ordinal.add_succ
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one_le_iff_pos {o : ordinal} : 1 ≤ o ↔ 0 < o
by rw [← succ_zero, succ_le_iff]
theorem
ordinal.one_le_iff_pos
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one_le_iff_ne_zero {o : ordinal} : 1 ≤ o ↔ o ≠ 0
by rw [one_le_iff_pos, ordinal.pos_iff_ne_zero]
theorem
ordinal.one_le_iff_ne_zero
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal", "ordinal.pos_iff_ne_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
succ_pos (o : ordinal) : 0 < succ o
bot_lt_succ o
theorem
ordinal.succ_pos
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
succ_ne_zero (o : ordinal) : succ o ≠ 0
ne_of_gt $ succ_pos o
theorem
ordinal.succ_ne_zero
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lt_one_iff_zero {a : ordinal} : a < 1 ↔ a = 0
by simpa using @lt_succ_bot_iff _ _ _ a _ _
theorem
ordinal.lt_one_iff_zero
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
le_one_iff {a : ordinal} : a ≤ 1 ↔ a = 0 ∨ a = 1
by simpa using @le_succ_bot_iff _ _ _ a _
theorem
ordinal.le_one_iff
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_succ (o : ordinal) : card (succ o) = card o + 1
by simp only [←add_one_eq_succ, card_add, card_one]
theorem
ordinal.card_succ
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_cast_succ (n : ℕ) : ↑n.succ = succ (n : ordinal)
rfl
theorem
ordinal.nat_cast_succ
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unique_Iio_one : unique (Iio (1 : ordinal))
{ default := ⟨0, zero_lt_one⟩, uniq := λ a, subtype.ext $ lt_one_iff_zero.1 a.prop }
instance
ordinal.unique_Iio_one
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal", "subtype.ext", "unique" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unique_out_one : unique (1 : ordinal).out.α
{ default := enum (<) 0 (by simp), uniq := λ a, begin rw ←enum_typein (<) a, unfold default, congr, rw ←lt_one_iff_zero, apply typein_lt_self end }
instance
ordinal.unique_out_one
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal", "unique" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one_out_eq (x : (1 : ordinal).out.α) : x = enum (<) 0 (by simp)
unique.eq_default x
theorem
ordinal.one_out_eq
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal", "unique.eq_default" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
typein_one_out (x : (1 : ordinal).out.α) : typein (<) x = 0
by rw [one_out_eq x, typein_enum]
theorem
ordinal.typein_one_out
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
typein_le_typein (r : α → α → Prop) [is_well_order α r] {x x' : α} : typein r x ≤ typein r x' ↔ ¬r x' x
by rw [←not_lt, typein_lt_typein]
lemma
ordinal.typein_le_typein
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "is_well_order" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
typein_le_typein' (o : ordinal) {x x' : o.out.α} : typein (<) x ≤ typein (<) x' ↔ x ≤ x'
by { rw typein_le_typein, exact not_lt }
lemma
ordinal.typein_le_typein'
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
enum_le_enum (r : α → α → Prop) [is_well_order α r] {o o' : ordinal} (ho : o < type r) (ho' : o' < type r) : ¬r (enum r o' ho') (enum r o ho) ↔ o ≤ o'
by rw [←@not_lt _ _ o' o, enum_lt_enum ho']
lemma
ordinal.enum_le_enum
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "is_well_order", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
enum_le_enum' (a : ordinal) {o o' : ordinal} (ho : o < type (<)) (ho' : o' < type (<)) : enum (<) o ho ≤ @enum a.out.α (<) _ o' ho' ↔ o ≤ o'
by rw [←enum_le_enum (<), ←not_lt]
lemma
ordinal.enum_le_enum'
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
enum_zero_le {r : α → α → Prop} [is_well_order α r] (h0 : 0 < type r) (a : α) : ¬ r a (enum r 0 h0)
by { rw [←enum_typein r a, enum_le_enum r], apply ordinal.zero_le }
theorem
ordinal.enum_zero_le
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "is_well_order", "ordinal.zero_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
enum_zero_le' {o : ordinal} (h0 : 0 < o) (a : o.out.α) : @enum o.out.α (<) _ 0 (by rwa type_lt) ≤ a
by { rw ←not_lt, apply enum_zero_le }
theorem
ordinal.enum_zero_le'
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
le_enum_succ {o : ordinal} (a : (succ o).out.α) : a ≤ @enum (succ o).out.α (<) _ o (by { rw type_lt, exact lt_succ o })
by { rw [←enum_typein (<) a, enum_le_enum', ←lt_succ_iff], apply typein_lt_self }
theorem
ordinal.le_enum_succ
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
enum_inj {r : α → α → Prop} [is_well_order α r] {o₁ o₂ : ordinal} (h₁ : o₁ < type r) (h₂ : o₂ < type r) : enum r o₁ h₁ = enum r o₂ h₂ ↔ o₁ = o₂
(typein.principal_seg r).subrel_iso.injective.eq_iff.trans subtype.mk_eq_mk
theorem
ordinal.enum_inj
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "is_well_order", "ordinal", "subtype.mk_eq_mk" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
enum_iso (r : α → α → Prop) [is_well_order α r] : subrel (<) (< type r) ≃r r
{ to_fun := λ x, enum r x.1 x.2, inv_fun := λ x, ⟨typein r x, typein_lt_type r x⟩, ..(typein.principal_seg r).subrel_iso }
def
ordinal.enum_iso
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "inv_fun", "is_well_order", "subrel" ]
A well order `r` is order isomorphic to the set of ordinals smaller than `type r`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
enum_iso_out (o : ordinal) : set.Iio o ≃o o.out.α
{ to_fun := λ x, enum (<) x.1 $ by { rw type_lt, exact x.2 }, inv_fun := λ x, ⟨typein (<) x, typein_lt_self x⟩, left_inv := λ ⟨o', h⟩, subtype.ext_val (typein_enum _ _), right_inv := λ h, enum_typein _ _, map_rel_iff' := by { rintros ⟨a, _⟩ ⟨b, _⟩, apply enum_le_enum' } }
def
ordinal.enum_iso_out
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "inv_fun", "ordinal", "set.Iio", "subtype.ext_val" ]
The order isomorphism between ordinals less than `o` and `o.out.α`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
out_order_bot_of_pos {o : ordinal} (ho : 0 < o) : order_bot o.out.α
⟨_, enum_zero_le' ho⟩
def
ordinal.out_order_bot_of_pos
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "order_bot", "ordinal" ]
`o.out.α` is an `order_bot` whenever `0 < o`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
enum_zero_eq_bot {o : ordinal} (ho : 0 < o) : enum (<) 0 (by rwa type_lt) = by { haveI H := out_order_bot_of_pos ho, exact ⊥ }
rfl
theorem
ordinal.enum_zero_eq_bot
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
univ : ordinal.{max (u + 1) v}
lift.{v (u+1)} (@type ordinal (<) _)
def
ordinal.univ
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
`univ.{u v}` is the order type of the ordinals of `Type u` as a member of `ordinal.{v}` (when `u < v`). It is an inaccessible cardinal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
univ_id : univ.{u (u+1)} = @type ordinal (<) _
lift_id _
theorem
ordinal.univ_id
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_univ : lift.{w} univ.{u v} = univ.{u (max v w)}
lift_lift _
theorem
ordinal.lift_univ
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
univ_umax : univ.{u (max (u+1) v)} = univ.{u v}
congr_fun lift_umax _
theorem
ordinal.univ_umax
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift.principal_seg : @principal_seg ordinal.{u} ordinal.{max (u+1) v} (<) (<)
⟨↑lift.initial_seg.{u (max (u+1) v)}, univ.{u v}, begin refine λ b, induction_on b _, introsI β s _, rw [univ, ← lift_umax], split; intro h, { rw ← lift_id (type s) at h ⊢, cases lift_type_lt.1 h with f, cases f with f a hf, existsi a, revert hf, apply induction_on a, introsI α r _ hf, refine lift...
def
ordinal.lift.principal_seg
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "principal_seg", "rel_embedding.of_monotone", "rel_iso.of_surjective" ]
Principal segment version of the lift operation on ordinals, embedding `ordinal.{u}` in `ordinal.{v}` as a principal segment when `u < v`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift.principal_seg_coe : (lift.principal_seg.{u v} : ordinal → ordinal) = lift.{max (u+1) v}
rfl
theorem
ordinal.lift.principal_seg_coe
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift.principal_seg_top : lift.principal_seg.top = univ
rfl
theorem
ordinal.lift.principal_seg_top
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift.principal_seg_top' : lift.principal_seg.{u (u+1)}.top = @type ordinal (<) _
by simp only [lift.principal_seg_top, univ_id]
theorem
ordinal.lift.principal_seg_top'
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_ordinal_out (o : ordinal) : #(o.out.α) = o.card
(ordinal.card_type _).symm.trans $ by rw ordinal.type_lt
theorem
cardinal.mk_ordinal_out
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal", "ordinal.card_type", "ordinal.type_lt" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord (c : cardinal) : ordinal
let F := λ α : Type u, ⨅ r : {r // is_well_order α r}, @type α r.1 r.2 in quot.lift_on c F begin suffices : ∀ {α β}, α ≈ β → F α ≤ F β, from λ α β h, (this h).antisymm (this (setoid.symm h)), rintros α β ⟨f⟩, refine le_cinfi_iff'.2 (λ i, _), haveI := @rel_embedding.is_well_order _ _ (f ⁻¹'o i.1) _ ↑(rel_iso.p...
def
cardinal.ord
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "cardinal", "cinfi_le'", "is_well_order", "ordinal", "rel_embedding.is_well_order", "rel_iso.preimage" ]
The ordinal corresponding to a cardinal `c` is the least ordinal whose cardinal is `c`. For the order-embedding version, see `ord.order_embedding`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord_eq_Inf (α : Type u) : ord (#α) = ⨅ r : {r // is_well_order α r}, @type α r.1 r.2
rfl
lemma
cardinal.ord_eq_Inf
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "is_well_order" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord_eq (α) : ∃ (r : α → α → Prop) [wo : is_well_order α r], ord (#α) = @type α r wo
let ⟨r, wo⟩ := infi_mem (λ r : {r // is_well_order α r}, @type α r.1 r.2) in ⟨r.1, r.2, wo.symm⟩
theorem
cardinal.ord_eq
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "infi_mem", "is_well_order" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord_le_type (r : α → α → Prop) [h : is_well_order α r] : ord (#α) ≤ type r
cinfi_le' _ (subtype.mk r h)
theorem
cardinal.ord_le_type
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "cinfi_le'", "is_well_order" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord_le {c o} : ord c ≤ o ↔ c ≤ o.card
induction_on c $ λ α, ordinal.induction_on o $ λ β s _, let ⟨r, _, e⟩ := ord_eq α in begin resetI, simp only [card_type], split; intro h, { rw e at h, exact let ⟨f⟩ := h in ⟨f.to_embedding⟩ }, { cases h with f, have g := rel_embedding.preimage f s, haveI := rel_embedding.is_well_order g, exact le_tran...
theorem
cardinal.ord_le
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal.induction_on", "rel_embedding.is_well_order", "rel_embedding.preimage" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
gc_ord_card : galois_connection ord card
λ _ _, ord_le
theorem
cardinal.gc_ord_card
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "galois_connection" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lt_ord {c o} : o < ord c ↔ o.card < c
gc_ord_card.lt_iff_lt
theorem
cardinal.lt_ord
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_ord (c) : (ord c).card = c
quotient.induction_on c $ λ α, let ⟨r, _, e⟩ := ord_eq α in by simp only [mk_def, e, card_type]
theorem
cardinal.card_ord
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
gci_ord_card : galois_coinsertion ord card
gc_ord_card.to_galois_coinsertion $ λ c, c.card_ord.le
def
cardinal.gci_ord_card
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "galois_coinsertion" ]
Galois coinsertion between `cardinal.ord` and `ordinal.card`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord_card_le (o : ordinal) : o.card.ord ≤ o
gc_ord_card.l_u_le _
theorem
cardinal.ord_card_le
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lt_ord_succ_card (o : ordinal) : o < (succ o.card).ord
lt_ord.2 $ lt_succ _
lemma
cardinal.lt_ord_succ_card
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord_strict_mono : strict_mono ord
gci_ord_card.strict_mono_l
theorem
cardinal.ord_strict_mono
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "strict_mono" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord_mono : monotone ord
gc_ord_card.monotone_l
theorem
cardinal.ord_mono
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "monotone" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord_le_ord {c₁ c₂} : ord c₁ ≤ ord c₂ ↔ c₁ ≤ c₂
gci_ord_card.l_le_l_iff
theorem
cardinal.ord_le_ord
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord_lt_ord {c₁ c₂} : ord c₁ < ord c₂ ↔ c₁ < c₂
ord_strict_mono.lt_iff_lt
theorem
cardinal.ord_lt_ord
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord_zero : ord 0 = 0
gc_ord_card.l_bot
theorem
cardinal.ord_zero
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord_nat (n : ℕ) : ord n = n
(ord_le.2 (card_nat n).ge).antisymm begin induction n with n IH, { apply ordinal.zero_le }, { exact succ_le_of_lt (IH.trans_lt $ ord_lt_ord.2 $ nat_cast_lt.2 (nat.lt_succ_self n)) } end
theorem
cardinal.ord_nat
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal.zero_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord_one : ord 1 = 1
by simpa using ord_nat 1
theorem
cardinal.ord_one
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_ord (c) : (ord c).lift = ord (lift c)
begin refine le_antisymm (le_of_forall_lt (λ a ha, _)) _, { rcases ordinal.lt_lift_iff.1 ha with ⟨a, rfl, h⟩, rwa [lt_ord, ← lift_card, lift_lt, ← lt_ord, ← ordinal.lift_lt] }, { rw [ord_le, ← lift_card, card_ord] } end
theorem
cardinal.lift_ord
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "le_of_forall_lt", "lift", "ordinal.lift_lt" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_ord_out (c : cardinal) : #c.ord.out.α = c
by simp
lemma
cardinal.mk_ord_out
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_typein_lt (r : α → α → Prop) [is_well_order α r] (x : α) (h : ord (#α) = type r) : card (typein r x) < #α
by { rw [←lt_ord, h], apply typein_lt_type }
lemma
cardinal.card_typein_lt
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "is_well_order" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_typein_out_lt (c : cardinal) (x : c.ord.out.α) : card (typein (<) x) < c
by { rw ←lt_ord, apply typein_lt_self }
lemma
cardinal.card_typein_out_lt
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord_injective : injective ord
by { intros c c' h, rw [←card_ord c, ←card_ord c', h] }
lemma
cardinal.ord_injective
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord.order_embedding : cardinal ↪o ordinal
rel_embedding.order_embedding_of_lt_embedding (rel_embedding.of_monotone cardinal.ord $ λ a b, cardinal.ord_lt_ord.2)
def
cardinal.ord.order_embedding
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "cardinal", "cardinal.ord", "ordinal", "rel_embedding.of_monotone", "rel_embedding.order_embedding_of_lt_embedding" ]
The ordinal corresponding to a cardinal `c` is the least ordinal whose cardinal is `c`. This is the order-embedding version. For the regular function, see `ord`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord.order_embedding_coe : (ord.order_embedding : cardinal → ordinal) = ord
rfl
theorem
cardinal.ord.order_embedding_coe
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "cardinal", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
univ
lift.{v (u+1)} (#ordinal)
def
cardinal.univ
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
The cardinal `univ` is the cardinality of ordinal `univ`, or equivalently the cardinal of `ordinal.{u}`, or `cardinal.{u}`, as an element of `cardinal.{v}` (when `u < v`).
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
univ_id : univ.{u (u+1)} = #ordinal
lift_id _
theorem
cardinal.univ_id
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_lt_univ (c : cardinal) : lift.{(u+1) u} c < univ.{u (u+1)}
by simpa only [lift.principal_seg_coe, lift_ord, lift_succ, ord_le, succ_le_iff] using le_of_lt (lift.principal_seg.{u (u+1)}.lt_top (succ c).ord)
theorem
cardinal.lift_lt_univ
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_lt_univ' (c : cardinal) : lift.{(max (u+1) v) u} c < univ.{u v}
by simpa only [lift_lift, lift_univ, univ_umax] using lift_lt.{_ (max (u+1) v)}.2 (lift_lt_univ c)
theorem
cardinal.lift_lt_univ'
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord_univ : ord univ.{u v} = ordinal.univ.{u v}
le_antisymm (ord_card_le _) $ le_of_forall_lt $ λ o h, lt_ord.2 begin rcases lift.principal_seg.{u v}.down.1 (by simpa only [lift.principal_seg_coe] using h) with ⟨o', rfl⟩, simp only [lift.principal_seg_coe], rw [← lift_card], apply lift_lt_univ' end
theorem
cardinal.ord_univ
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "le_of_forall_lt" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lt_univ {c} : c < univ.{u (u+1)} ↔ ∃ c', c = lift.{(u+1) u} c'
⟨λ h, begin have := ord_lt_ord.2 h, rw ord_univ at this, cases lift.principal_seg.{u (u+1)}.down.1 (by simpa only [lift.principal_seg_top]) with o e, have := card_ord c, rw [← e, lift.principal_seg_coe, ← lift_card] at this, exact ⟨_, this.symm⟩ end, λ ⟨c', e⟩, e.symm ▸ lift_lt_univ _⟩
theorem
cardinal.lt_univ
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lt_univ' {c} : c < univ.{u v} ↔ ∃ c', c = lift.{(max (u+1) v) u} c'
⟨λ h, let ⟨a, e, h'⟩ := lt_lift_iff.1 h in begin rw [← univ_id] at h', rcases lt_univ.{u}.1 h' with ⟨c', rfl⟩, exact ⟨c', by simp only [e.symm, lift_lift]⟩ end, λ ⟨c', e⟩, e.symm ▸ lift_lt_univ' _⟩
theorem
cardinal.lt_univ'
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
small_iff_lift_mk_lt_univ {α : Type u} : small.{v} α ↔ cardinal.lift (#α) < univ.{v (max u (v + 1))}
begin rw lt_univ', split, { rintro ⟨β, e⟩, exact ⟨#β, lift_mk_eq.{u _ (v + 1)}.2 e⟩ }, { rintro ⟨c, hc⟩, exact ⟨⟨c.out, lift_mk_eq.{u _ (v + 1)}.1 (hc.trans (congr rfl c.mk_out.symm))⟩⟩ } end
theorem
cardinal.small_iff_lift_mk_lt_univ
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "cardinal.lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_univ : card univ = cardinal.univ
rfl
theorem
ordinal.card_univ
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "cardinal.univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_le_card {o} {n : ℕ} : (n : cardinal) ≤ card o ↔ (n : ordinal) ≤ o
by rw [← cardinal.ord_le, cardinal.ord_nat]
theorem
ordinal.nat_le_card
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "cardinal", "cardinal.ord_le", "cardinal.ord_nat", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_lt_card {o} {n : ℕ} : (n : cardinal) < card o ↔ (n : ordinal) < o
by { rw [←succ_le_iff, ←succ_le_iff, ←nat_succ, nat_le_card], refl }
theorem
ordinal.nat_lt_card
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "cardinal", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_lt_nat {o} {n : ℕ} : card o < n ↔ o < n
lt_iff_lt_of_le_iff_le nat_le_card
theorem
ordinal.card_lt_nat
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "lt_iff_lt_of_le_iff_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_le_nat {o} {n : ℕ} : card o ≤ n ↔ o ≤ n
le_iff_le_iff_lt_iff_lt.2 nat_lt_card
theorem
ordinal.card_le_nat
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_eq_nat {o} {n : ℕ} : card o = n ↔ o = n
by simp only [le_antisymm_iff, card_le_nat, nat_le_card]
theorem
ordinal.card_eq_nat
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
type_fintype (r : α → α → Prop) [is_well_order α r] [fintype α] : type r = fintype.card α
by rw [←card_eq_nat, card_type, mk_fintype]
theorem
ordinal.type_fintype
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[ "fintype", "fintype.card", "is_well_order" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
type_fin (n : ℕ) : @type (fin n) (<) _ = n
by simp
theorem
ordinal.type_fin
set_theory.ordinal
src/set_theory/ordinal/basic.lean
[ "data.sum.order", "order.initial_seg", "set_theory.cardinal.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
CNF_rec (b : ordinal) {C : ordinal → Sort*} (H0 : C 0) (H : ∀ o, o ≠ 0 → C (o % b ^ log b o) → C o) : ∀ o, C o
| o := if ho : o = 0 then by rwa ho else let hwf := mod_opow_log_lt_self b ho in H o ho (CNF_rec (o % b ^ log b o)) using_well_founded {dec_tac := `[assumption]}
def
ordinal.CNF_rec
set_theory.ordinal
src/set_theory/ordinal/cantor_normal_form.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
Inducts on the base `b` expansion of an ordinal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
CNF_rec_zero {C : ordinal → Sort*} (b : ordinal) (H0 : C 0) (H : ∀ o, o ≠ 0 → C (o % b ^ log b o) → C o) : @CNF_rec b C H0 H 0 = H0
by { rw [CNF_rec, dif_pos rfl], refl }
theorem
ordinal.CNF_rec_zero
set_theory.ordinal
src/set_theory/ordinal/cantor_normal_form.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
CNF_rec_pos (b : ordinal) {o : ordinal} {C : ordinal → Sort*} (ho : o ≠ 0) (H0 : C 0) (H : ∀ o, o ≠ 0 → C (o % b ^ log b o) → C o) : @CNF_rec b C H0 H o = H o ho (@CNF_rec b C H0 H _)
by rw [CNF_rec, dif_neg ho]
theorem
ordinal.CNF_rec_pos
set_theory.ordinal
src/set_theory/ordinal/cantor_normal_form.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
CNF (b o : ordinal) : list (ordinal × ordinal)
CNF_rec b [] (λ o ho IH, (log b o, o / b ^ log b o) :: IH) o
def
ordinal.CNF
set_theory.ordinal
src/set_theory/ordinal/cantor_normal_form.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
The Cantor normal form of an ordinal `o` is the list of coefficients and exponents in the base-`b` expansion of `o`. We special-case `CNF 0 o = CNF 1 o = [(0, o)]` for `o ≠ 0`. `CNF b (b ^ u₁ * v₁ + b ^ u₂ * v₂) = [(u₁, v₁), (u₂, v₂)]`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
CNF_zero (b : ordinal) : CNF b 0 = []
CNF_rec_zero b _ _
theorem
ordinal.CNF_zero
set_theory.ordinal
src/set_theory/ordinal/cantor_normal_form.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
CNF_ne_zero {b o : ordinal} (ho : o ≠ 0) : CNF b o = (log b o, o / b ^ log b o) :: CNF b (o % b ^ log b o)
CNF_rec_pos b ho _ _
theorem
ordinal.CNF_ne_zero
set_theory.ordinal
src/set_theory/ordinal/cantor_normal_form.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
Recursive definition for the Cantor normal form.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
zero_CNF {o : ordinal} (ho : o ≠ 0) : CNF 0 o = [⟨0, o⟩]
by simp [CNF_ne_zero ho]
theorem
ordinal.zero_CNF
set_theory.ordinal
src/set_theory/ordinal/cantor_normal_form.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one_CNF {o : ordinal} (ho : o ≠ 0) : CNF 1 o = [⟨0, o⟩]
by simp [CNF_ne_zero ho]
theorem
ordinal.one_CNF
set_theory.ordinal
src/set_theory/ordinal/cantor_normal_form.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
CNF_of_le_one {b o : ordinal} (hb : b ≤ 1) (ho : o ≠ 0) : CNF b o = [⟨0, o⟩]
begin rcases le_one_iff.1 hb with rfl | rfl, { exact zero_CNF ho }, { exact one_CNF ho } end
theorem
ordinal.CNF_of_le_one
set_theory.ordinal
src/set_theory/ordinal/cantor_normal_form.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
CNF_of_lt {b o : ordinal} (ho : o ≠ 0) (hb : o < b) : CNF b o = [⟨0, o⟩]
by simp [CNF_ne_zero ho, log_eq_zero hb]
theorem
ordinal.CNF_of_lt
set_theory.ordinal
src/set_theory/ordinal/cantor_normal_form.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
CNF_foldr (b o : ordinal) : (CNF b o).foldr (λ p r, b ^ p.1 * p.2 + r) 0 = o
CNF_rec b (by { rw CNF_zero, refl }) (λ o ho IH, by rw [CNF_ne_zero ho, foldr_cons, IH, div_add_mod]) o
theorem
ordinal.CNF_foldr
set_theory.ordinal
src/set_theory/ordinal/cantor_normal_form.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
Evaluating the Cantor normal form of an ordinal returns the ordinal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
CNF_fst_le_log {b o : ordinal.{u}} {x : ordinal × ordinal} : x ∈ CNF b o → x.1 ≤ log b o
begin refine CNF_rec b _ (λ o ho H, _) o, { simp }, { rw [CNF_ne_zero ho, mem_cons_iff], rintro (rfl | h), { exact le_rfl }, { exact (H h).trans (log_mono_right _ (mod_opow_log_lt_self b ho).le) } } end
theorem
ordinal.CNF_fst_le_log
set_theory.ordinal
src/set_theory/ordinal/cantor_normal_form.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "le_rfl", "mem_cons_iff", "ordinal" ]
Every exponent in the Cantor normal form `CNF b o` is less or equal to `log b o`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
CNF_fst_le {b o : ordinal.{u}} {x : ordinal × ordinal} (h : x ∈ CNF b o) : x.1 ≤ o
(CNF_fst_le_log h).trans $ log_le_self _ _
theorem
ordinal.CNF_fst_le
set_theory.ordinal
src/set_theory/ordinal/cantor_normal_form.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
Every exponent in the Cantor normal form `CNF b o` is less or equal to `o`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
CNF_lt_snd {b o : ordinal.{u}} {x : ordinal × ordinal} : x ∈ CNF b o → 0 < x.2
begin refine CNF_rec b _ (λ o ho IH, _) o, { simp }, { rw CNF_ne_zero ho, rintro (rfl | h), { exact div_opow_log_pos b ho }, { exact IH h } } end
theorem
ordinal.CNF_lt_snd
set_theory.ordinal
src/set_theory/ordinal/cantor_normal_form.lean
[ "set_theory.ordinal.arithmetic", "set_theory.ordinal.exponential" ]
[ "ordinal" ]
Every coefficient in a Cantor normal form is positive.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83