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nat_power_aleph_0 {n : ℕ} (hn : 2 ≤ n) : (n ^ aleph_0.{u} : cardinal.{u}) = 𝔠
nat_power_eq le_rfl hn
lemma
cardinal.nat_power_aleph_0
set_theory.cardinal
src/set_theory/cardinal/continuum.lean
[ "set_theory.cardinal.ordinal" ]
[ "le_rfl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuum_power_aleph_0 : continuum.{u} ^ aleph_0.{u} = 𝔠
by rw [←two_power_aleph_0, ←power_mul, mul_eq_left le_rfl le_rfl aleph_0_ne_zero]
lemma
cardinal.continuum_power_aleph_0
set_theory.cardinal
src/set_theory/cardinal/continuum.lean
[ "set_theory.cardinal.ordinal" ]
[ "le_rfl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_unit_iff : is_unit a ↔ a = 1
begin refine ⟨λ h, _, by { rintro rfl, exact is_unit_one }⟩, rcases eq_or_ne a 0 with rfl | ha, { exact (not_is_unit_zero h).elim }, rw is_unit_iff_forall_dvd at h, cases h 1 with t ht, rw [eq_comm, mul_eq_one_iff'] at ht, { exact ht.1 }, all_goals { rwa one_le_iff_ne_zero }, { rintro rfl, rw mul_...
lemma
cardinal.is_unit_iff
set_theory.cardinal
src/set_theory/cardinal/divisibility.lean
[ "algebra.is_prime_pow", "set_theory.cardinal.ordinal" ]
[ "eq_or_ne", "is_unit", "is_unit_iff_forall_dvd", "is_unit_one", "mul_eq_one_iff'", "mul_zero", "not_is_unit_zero", "zero_ne_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
le_of_dvd : ∀ {a b : cardinal}, b ≠ 0 → a ∣ b → a ≤ b
| a _ b0 ⟨b, rfl⟩ := by simpa only [mul_one] using mul_le_mul_left' (one_le_iff_ne_zero.2 (λ h : b = 0, by simpa only [h, mul_zero] using b0)) a
theorem
cardinal.le_of_dvd
set_theory.cardinal
src/set_theory/cardinal/divisibility.lean
[ "algebra.is_prime_pow", "set_theory.cardinal.ordinal" ]
[ "cardinal", "mul_le_mul_left'", "mul_one", "mul_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dvd_of_le_of_aleph_0_le (ha : a ≠ 0) (h : a ≤ b) (hb : ℵ₀ ≤ b) : a ∣ b
⟨b, (mul_eq_right hb h ha).symm⟩
lemma
cardinal.dvd_of_le_of_aleph_0_le
set_theory.cardinal
src/set_theory/cardinal/divisibility.lean
[ "algebra.is_prime_pow", "set_theory.cardinal.ordinal" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prime_of_aleph_0_le (ha : ℵ₀ ≤ a) : prime a
begin refine ⟨(aleph_0_pos.trans_le ha).ne', _, λ b c hbc, _⟩, { rw is_unit_iff, exact (one_lt_aleph_0.trans_le ha).ne' }, cases eq_or_ne (b * c) 0 with hz hz, { rcases mul_eq_zero.mp hz with rfl | rfl; simp }, wlog h : c ≤ b, { cases le_total c b; [skip, rw or_comm]; apply_assumption, assumption', ...
lemma
cardinal.prime_of_aleph_0_le
set_theory.cardinal
src/set_theory/cardinal/divisibility.lean
[ "algebra.is_prime_pow", "set_theory.cardinal.ordinal" ]
[ "eq_or_ne", "max_def'", "mul_comm", "prime" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
not_irreducible_of_aleph_0_le (ha : ℵ₀ ≤ a) : ¬irreducible a
begin rw [irreducible_iff, not_and_distrib], refine or.inr (λ h, _), simpa [mul_aleph_0_eq ha, is_unit_iff, (one_lt_aleph_0.trans_le ha).ne', one_lt_aleph_0.ne'] using h a ℵ₀ end
lemma
cardinal.not_irreducible_of_aleph_0_le
set_theory.cardinal
src/set_theory/cardinal/divisibility.lean
[ "algebra.is_prime_pow", "set_theory.cardinal.ordinal" ]
[ "irreducible", "irreducible_iff", "not_and_distrib" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_coe_dvd_iff : (n : cardinal) ∣ m ↔ n ∣ m
begin refine ⟨_, λ ⟨h, ht⟩, ⟨h, by exact_mod_cast ht⟩⟩, rintro ⟨k, hk⟩, have : ↑m < ℵ₀ := nat_lt_aleph_0 m, rw [hk, mul_lt_aleph_0_iff] at this, rcases this with h | h | ⟨-, hk'⟩, iterate 2 { simp only [h, mul_zero, zero_mul, nat.cast_eq_zero] at hk, simp [hk] }, lift k to ℕ using hk', exact ⟨k, by exa...
lemma
cardinal.nat_coe_dvd_iff
set_theory.cardinal
src/set_theory/cardinal/divisibility.lean
[ "algebra.is_prime_pow", "set_theory.cardinal.ordinal" ]
[ "cardinal", "lift", "mul_zero", "nat.cast_eq_zero", "zero_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_is_prime_iff : prime (n : cardinal) ↔ n.prime
begin simp only [prime, nat.prime_iff], refine and_congr (by simp) (and_congr _ ⟨λ h b c hbc, _, λ h b c hbc, _⟩), { simp only [is_unit_iff, nat.is_unit_iff], exact_mod_cast iff.rfl }, { exact_mod_cast h b c (by exact_mod_cast hbc) }, cases lt_or_le (b * c) ℵ₀ with h' h', { rcases mul_lt_aleph_0_iff.mp ...
lemma
cardinal.nat_is_prime_iff
set_theory.cardinal
src/set_theory/cardinal/divisibility.lean
[ "algebra.is_prime_pow", "set_theory.cardinal.ordinal" ]
[ "cardinal", "lift", "mul_comm", "mul_eq_zero", "nat.is_unit_iff", "nat.prime_iff", "prime", "zero_dvd_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_prime_iff {a : cardinal} : prime a ↔ ℵ₀ ≤ a ∨ ∃ p : ℕ, a = p ∧ p.prime
begin cases le_or_lt ℵ₀ a with h h, { simp [h] }, lift a to ℕ using id h, simp [not_le.mpr h] end
lemma
cardinal.is_prime_iff
set_theory.cardinal
src/set_theory/cardinal/divisibility.lean
[ "algebra.is_prime_pow", "set_theory.cardinal.ordinal" ]
[ "cardinal", "lift", "prime" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_prime_pow_iff {a : cardinal} : is_prime_pow a ↔ ℵ₀ ≤ a ∨ ∃ n : ℕ, a = n ∧ is_prime_pow n
begin by_cases h : ℵ₀ ≤ a, { simp [h, (prime_of_aleph_0_le h).is_prime_pow] }, lift a to ℕ using not_le.mp h, simp only [h, nat.cast_inj, exists_eq_left', false_or, is_prime_pow_nat_iff], rw is_prime_pow_def, refine ⟨_, λ ⟨p, k, hp, hk, h⟩, ⟨p, k, nat_is_prime_iff.2 hp, by exact_mod_cast and.intro hk h⟩⟩, ...
lemma
cardinal.is_prime_pow_iff
set_theory.cardinal
src/set_theory/cardinal/divisibility.lean
[ "algebra.is_prime_pow", "set_theory.cardinal.ordinal" ]
[ "cardinal", "exists_eq_left'", "is_prime_pow", "is_prime_pow_def", "is_prime_pow_nat_iff", "lift", "nat.cast_inj" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card (α : Type*) : ℕ
(mk α).to_nat
def
nat.card
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "to_nat" ]
`nat.card α` is the cardinality of `α` as a natural number. If `α` is infinite, `nat.card α = 0`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_eq_fintype_card [fintype α] : nat.card α = fintype.card α
mk_to_nat_eq_card
lemma
nat.card_eq_fintype_card
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "fintype", "fintype.card", "nat.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_eq_zero_of_infinite [infinite α] : nat.card α = 0
mk_to_nat_of_infinite
lemma
nat.card_eq_zero_of_infinite
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "infinite", "nat.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finite_of_card_ne_zero (h : nat.card α ≠ 0) : finite α
not_infinite_iff_finite.mp $ h ∘ @nat.card_eq_zero_of_infinite α
lemma
nat.finite_of_card_ne_zero
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "finite", "nat.card", "nat.card_eq_zero_of_infinite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_congr (f : α ≃ β) : nat.card α = nat.card β
cardinal.to_nat_congr f
lemma
nat.card_congr
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "cardinal.to_nat_congr", "nat.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_eq_of_bijective (f : α → β) (hf : function.bijective f) : nat.card α = nat.card β
card_congr (equiv.of_bijective f hf)
lemma
nat.card_eq_of_bijective
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "equiv.of_bijective", "nat.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_eq_of_equiv_fin {α : Type*} {n : ℕ} (f : α ≃ fin n) : nat.card α = n
by simpa using card_congr f
lemma
nat.card_eq_of_equiv_fin
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "nat.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equiv_fin_of_card_pos {α : Type*} (h : nat.card α ≠ 0) : α ≃ fin (nat.card α)
begin casesI fintype_or_infinite α, { simpa using fintype.equiv_fin α }, { simpa using h }, end
def
nat.equiv_fin_of_card_pos
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "fintype.equiv_fin", "fintype_or_infinite", "nat.card" ]
If the cardinality is positive, that means it is a finite type, so there is an equivalence between `α` and `fin (nat.card α)`. See also `finite.equiv_fin`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_of_subsingleton (a : α) [subsingleton α] : nat.card α = 1
begin letI := fintype.of_subsingleton a, rw [card_eq_fintype_card, fintype.card_of_subsingleton a] end
lemma
nat.card_of_subsingleton
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "fintype.card_of_subsingleton", "fintype.of_subsingleton", "nat.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_unique [unique α] : nat.card α = 1
card_of_subsingleton default
lemma
nat.card_unique
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "nat.card", "unique" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_eq_one_iff_unique : nat.card α = 1 ↔ subsingleton α ∧ nonempty α
cardinal.to_nat_eq_one_iff_unique
lemma
nat.card_eq_one_iff_unique
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "cardinal.to_nat_eq_one_iff_unique", "nat.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_eq_two_iff : nat.card α = 2 ↔ ∃ x y : α, x ≠ y ∧ {x, y} = @set.univ α
(to_nat_eq_iff two_ne_zero).trans $ iff.trans (by rw [nat.cast_two]) mk_eq_two_iff
lemma
nat.card_eq_two_iff
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "nat.card", "nat.cast_two", "two_ne_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_eq_two_iff' (x : α) : nat.card α = 2 ↔ ∃! y, y ≠ x
(to_nat_eq_iff two_ne_zero).trans $ iff.trans (by rw [nat.cast_two]) (mk_eq_two_iff' x)
lemma
nat.card_eq_two_iff'
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "nat.card", "nat.cast_two", "two_ne_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_of_is_empty [is_empty α] : nat.card α = 0
by simp
theorem
nat.card_of_is_empty
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "is_empty", "nat.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_prod (α β : Type*) : nat.card (α × β) = nat.card α * nat.card β
by simp only [nat.card, mk_prod, to_nat_mul, to_nat_lift]
lemma
nat.card_prod
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "nat.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_ulift (α : Type*) : nat.card (ulift α) = nat.card α
card_congr equiv.ulift
lemma
nat.card_ulift
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "equiv.ulift", "nat.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_plift (α : Type*) : nat.card (plift α) = nat.card α
card_congr equiv.plift
lemma
nat.card_plift
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "equiv.plift", "nat.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_pi {β : α → Type*} [fintype α] : nat.card (Π a, β a) = ∏ a, nat.card (β a)
by simp_rw [nat.card, mk_pi, prod_eq_of_fintype, to_nat_lift, to_nat_finset_prod]
lemma
nat.card_pi
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "fintype", "nat.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_fun [finite α] : nat.card (α → β) = nat.card β ^ nat.card α
begin haveI := fintype.of_finite α, rw [nat.card_pi, finset.prod_const, finset.card_univ, ←nat.card_eq_fintype_card], end
lemma
nat.card_fun
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "finite", "finset.card_univ", "finset.prod_const", "fintype.of_finite", "nat.card", "nat.card_pi" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_zmod (n : ℕ) : nat.card (zmod n) = n
begin cases n, { exact nat.card_eq_zero_of_infinite }, { rw [nat.card_eq_fintype_card, zmod.card] }, end
lemma
nat.card_zmod
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "nat.card", "nat.card_eq_fintype_card", "nat.card_eq_zero_of_infinite", "zmod", "zmod.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card (α : Type*) : part_enat
(mk α).to_part_enat
def
part_enat.card
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "part_enat" ]
`part_enat.card α` is the cardinality of `α` as an extended natural number. If `α` is infinite, `part_enat.card α = ⊤`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_eq_coe_fintype_card [fintype α] : card α = fintype.card α
mk_to_part_enat_eq_coe_card
lemma
part_enat.card_eq_coe_fintype_card
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "fintype", "fintype.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_eq_top_of_infinite [infinite α] : card α = ⊤
mk_to_part_enat_of_infinite
lemma
part_enat.card_eq_top_of_infinite
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "infinite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_congr {α : Type*} {β : Type*} (f : α ≃ β) : part_enat.card α = part_enat.card β
cardinal.to_part_enat_congr f
lemma
part_enat.card_congr
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "cardinal.to_part_enat_congr", "part_enat.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_ulift (α : Type*) : card (ulift α) = card α
card_congr equiv.ulift
lemma
part_enat.card_ulift
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "equiv.ulift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_plift (α : Type*) : card (plift α) = card α
card_congr equiv.plift
lemma
part_enat.card_plift
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "equiv.plift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_image_of_inj_on {α : Type*} {β : Type*} {f : α → β} {s : set α} (h : set.inj_on f s) : card (f '' s) = card s
card_congr (equiv.set.image_of_inj_on f s h).symm
lemma
part_enat.card_image_of_inj_on
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "equiv.set.image_of_inj_on", "set.inj_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_image_of_injective {α : Type*} {β : Type*} (f : α → β) (s : set α) (h : function.injective f) : card (f '' s) = card s
card_image_of_inj_on (set.inj_on_of_injective h s)
lemma
part_enat.card_image_of_injective
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "set.inj_on_of_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.cardinal.coe_nat_le_to_part_enat_iff {n : ℕ} {c : cardinal} : ↑n ≤ to_part_enat c ↔ ↑n ≤ c
by rw [← to_part_enat_cast n, to_part_enat_le_iff_le_of_le_aleph_0 (le_of_lt (nat_lt_aleph_0 n))]
lemma
cardinal.coe_nat_le_to_part_enat_iff
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.cardinal.to_part_enat_le_coe_nat_iff {c : cardinal} {n : ℕ} : to_part_enat c ≤ n ↔ c ≤ n
by rw [← to_part_enat_cast n, to_part_enat_le_iff_le_of_lt_aleph_0 (nat_lt_aleph_0 n)]
lemma
cardinal.to_part_enat_le_coe_nat_iff
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.cardinal.coe_nat_eq_to_part_enat_iff {n : ℕ} {c : cardinal} : ↑n = to_part_enat c ↔ ↑n = c
by rw [le_antisymm_iff, le_antisymm_iff, cardinal.coe_nat_le_to_part_enat_iff, cardinal.to_part_enat_le_coe_nat_iff]
lemma
cardinal.coe_nat_eq_to_part_enat_iff
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "cardinal", "cardinal.coe_nat_le_to_part_enat_iff", "cardinal.to_part_enat_le_coe_nat_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.cardinal.to_part_enat_eq_coe_nat_iff {c : cardinal} {n : ℕ} : to_part_enat c = n ↔ c = n
by rw [eq_comm, cardinal.coe_nat_eq_to_part_enat_iff, eq_comm]
lemma
cardinal.to_part_enat_eq_coe_nat_iff
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "cardinal", "cardinal.coe_nat_eq_to_part_enat_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.cardinal.coe_nat_lt_coe_iff_lt {n : ℕ} {c : cardinal} : ↑n < to_part_enat c ↔ ↑n < c
by simp only [← not_le, cardinal.to_part_enat_le_coe_nat_iff]
lemma
cardinal.coe_nat_lt_coe_iff_lt
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "cardinal", "cardinal.to_part_enat_le_coe_nat_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.cardinal.lt_coe_nat_iff_lt {n : ℕ} {c : cardinal} : to_part_enat c < n ↔ c < n
by simp only [← not_le, cardinal.coe_nat_le_to_part_enat_iff]
lemma
cardinal.lt_coe_nat_iff_lt
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "cardinal", "cardinal.coe_nat_le_to_part_enat_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_eq_zero_iff_empty (α : Type*) : card α = 0 ↔ is_empty α
begin rw ← cardinal.mk_eq_zero_iff, conv_rhs { rw ← nat.cast_zero }, rw ← cardinal.to_part_enat_eq_coe_nat_iff, simp only [part_enat.card, nat.cast_zero] end
lemma
part_enat.card_eq_zero_iff_empty
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "cardinal.mk_eq_zero_iff", "cardinal.to_part_enat_eq_coe_nat_iff", "is_empty", "nat.cast_zero", "part_enat.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_le_one_iff_subsingleton (α : Type*) : card α ≤ 1 ↔ subsingleton α
begin rw ← le_one_iff_subsingleton, conv_rhs { rw ← nat.cast_one}, rw ← cardinal.to_part_enat_le_coe_nat_iff, simp only [part_enat.card, nat.cast_one] end
lemma
part_enat.card_le_one_iff_subsingleton
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "cardinal.to_part_enat_le_coe_nat_iff", "nat.cast_one", "part_enat.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one_lt_card_iff_nontrivial (α : Type*) : 1 < card α ↔ nontrivial α
begin rw ← one_lt_iff_nontrivial, conv_rhs { rw ← nat.cast_one}, rw ← cardinal.coe_nat_lt_coe_iff_lt, simp only [part_enat.card, nat.cast_one] end
lemma
part_enat.one_lt_card_iff_nontrivial
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "cardinal.coe_nat_lt_coe_iff_lt", "nat.cast_one", "nontrivial", "part_enat.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_finite_of_card {α : Type*} {n : ℕ} (hα : part_enat.card α = n) : finite α
begin apply or.resolve_right (finite_or_infinite α), intro h, resetI, apply part_enat.coe_ne_top n, rw ← hα, exact part_enat.card_eq_top_of_infinite, end
lemma
part_enat.is_finite_of_card
set_theory.cardinal
src/set_theory/cardinal/finite.lean
[ "data.zmod.defs", "set_theory.cardinal.basic" ]
[ "finite", "finite_or_infinite", "part_enat.card", "part_enat.card_eq_top_of_infinite", "part_enat.coe_ne_top" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord_is_limit {c} (co : ℵ₀ ≤ c) : (ord c).is_limit
begin refine ⟨λ h, aleph_0_ne_zero _, λ a, lt_imp_lt_of_le_imp_le (λ h, _)⟩, { rw [←ordinal.le_zero, ord_le] at h, simpa only [card_zero, nonpos_iff_eq_zero] using co.trans h }, { rw ord_le at h ⊢, rwa [←@add_one_of_aleph_0_le (card a), ←card_succ], rw [←ord_le, ←le_succ_of_is_limit, ord_le], { ex...
theorem
cardinal.ord_is_limit
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "lt_imp_lt_of_le_imp_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_idx.initial_seg : @initial_seg cardinal ordinal (<) (<)
@rel_embedding.collapse cardinal ordinal (<) (<) _ cardinal.ord.order_embedding.lt_embedding
def
cardinal.aleph_idx.initial_seg
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "cardinal", "initial_seg", "ordinal", "rel_embedding.collapse" ]
The `aleph'` index function, which gives the ordinal index of a cardinal. (The `aleph'` part is because unlike `aleph` this counts also the finite stages. So `aleph_idx n = n`, `aleph_idx ω = ω`, `aleph_idx ℵ₁ = ω + 1` and so on.) In this definition, we register additionally that this function is an initial seg...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_idx : cardinal → ordinal
aleph_idx.initial_seg
def
cardinal.aleph_idx
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "cardinal", "ordinal" ]
The `aleph'` index function, which gives the ordinal index of a cardinal. (The `aleph'` part is because unlike `aleph` this counts also the finite stages. So `aleph_idx n = n`, `aleph_idx ω = ω`, `aleph_idx ℵ₁ = ω + 1` and so on.) For an upgraded version stating that the range is everything, see `aleph_idx.rel_...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_idx.initial_seg_coe : (aleph_idx.initial_seg : cardinal → ordinal) = aleph_idx
rfl
theorem
cardinal.aleph_idx.initial_seg_coe
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "cardinal", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_idx_lt {a b} : aleph_idx a < aleph_idx b ↔ a < b
aleph_idx.initial_seg.to_rel_embedding.map_rel_iff
theorem
cardinal.aleph_idx_lt
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_idx_le {a b} : aleph_idx a ≤ aleph_idx b ↔ a ≤ b
by rw [← not_lt, ← not_lt, aleph_idx_lt]
theorem
cardinal.aleph_idx_le
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_idx.init {a b} : b < aleph_idx a → ∃ c, aleph_idx c = b
aleph_idx.initial_seg.init
theorem
cardinal.aleph_idx.init
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_idx.rel_iso : @rel_iso cardinal.{u} ordinal.{u} (<) (<)
@rel_iso.of_surjective cardinal.{u} ordinal.{u} (<) (<) aleph_idx.initial_seg.{u} $ (initial_seg.eq_or_principal aleph_idx.initial_seg.{u}).resolve_right $ λ ⟨o, e⟩, begin have : ∀ c, aleph_idx c < o := λ c, (e _).2 ⟨_, rfl⟩, refine ordinal.induction_on o _ this, introsI α r _ h, let s := ⨆ a, inv_fun aleph_idx (...
def
cardinal.aleph_idx.rel_iso
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "initial_seg.eq_or_principal", "inv_fun", "le_csupr", "left_inverse_inv_fun", "ordinal.enum", "ordinal.induction_on", "ordinal.typein", "rel_iso", "rel_iso.of_surjective" ]
The `aleph'` index function, which gives the ordinal index of a cardinal. (The `aleph'` part is because unlike `aleph` this counts also the finite stages. So `aleph_idx n = n`, `aleph_idx ℵ₀ = ω`, `aleph_idx ℵ₁ = ω + 1` and so on.) In this version, we register additionally that this function is an order isomorp...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_idx.rel_iso_coe : (aleph_idx.rel_iso : cardinal → ordinal) = aleph_idx
rfl
theorem
cardinal.aleph_idx.rel_iso_coe
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "cardinal", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
type_cardinal : @type cardinal (<) _ = ordinal.univ.{u (u+1)}
by rw ordinal.univ_id; exact quotient.sound ⟨aleph_idx.rel_iso⟩
theorem
cardinal.type_cardinal
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "cardinal", "ordinal.univ_id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_cardinal : #cardinal = univ.{u (u+1)}
by simpa only [card_type, card_univ] using congr_arg card type_cardinal
theorem
cardinal.mk_cardinal
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph'.rel_iso
cardinal.aleph_idx.rel_iso.symm
def
cardinal.aleph'.rel_iso
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[]
The `aleph'` function gives the cardinals listed by their ordinal index, and is the inverse of `aleph_idx`. `aleph' n = n`, `aleph' ω = ω`, `aleph' (ω + 1) = succ ℵ₀`, etc. In this version, we register additionally that this function is an order isomorphism between ordinals and cardinals. For the basic functi...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph' : ordinal → cardinal
aleph'.rel_iso
def
cardinal.aleph'
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "cardinal", "ordinal" ]
The `aleph'` function gives the cardinals listed by their ordinal index, and is the inverse of `aleph_idx`. `aleph' n = n`, `aleph' ω = ω`, `aleph' (ω + 1) = succ ℵ₀`, etc.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph'.rel_iso_coe : (aleph'.rel_iso : ordinal → cardinal) = aleph'
rfl
theorem
cardinal.aleph'.rel_iso_coe
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "cardinal", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph'_lt {o₁ o₂ : ordinal} : aleph' o₁ < aleph' o₂ ↔ o₁ < o₂
aleph'.rel_iso.map_rel_iff
theorem
cardinal.aleph'_lt
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph'_le {o₁ o₂ : ordinal} : aleph' o₁ ≤ aleph' o₂ ↔ o₁ ≤ o₂
le_iff_le_iff_lt_iff_lt.2 aleph'_lt
theorem
cardinal.aleph'_le
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph'_aleph_idx (c : cardinal) : aleph' c.aleph_idx = c
cardinal.aleph_idx.rel_iso.to_equiv.symm_apply_apply c
theorem
cardinal.aleph'_aleph_idx
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_idx_aleph' (o : ordinal) : (aleph' o).aleph_idx = o
cardinal.aleph_idx.rel_iso.to_equiv.apply_symm_apply o
theorem
cardinal.aleph_idx_aleph'
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph'_zero : aleph' 0 = 0
by { rw [← nonpos_iff_eq_zero, ← aleph'_aleph_idx 0, aleph'_le], apply ordinal.zero_le }
theorem
cardinal.aleph'_zero
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal.zero_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph'_succ {o : ordinal} : aleph' (succ o) = succ (aleph' o)
begin apply (succ_le_of_lt $ aleph'_lt.2 $ lt_succ o).antisymm' (cardinal.aleph_idx_le.1 $ _), rw [aleph_idx_aleph', succ_le_iff, ← aleph'_lt, aleph'_aleph_idx], apply lt_succ end
theorem
cardinal.aleph'_succ
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "antisymm'", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph'_nat : ∀ n : ℕ, aleph' n = n
| 0 := aleph'_zero | (n+1) := show aleph' (succ n) = n.succ, by rw [aleph'_succ, aleph'_nat, nat_succ]
theorem
cardinal.aleph'_nat
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph'_le_of_limit {o : ordinal} (l : o.is_limit) {c} : aleph' o ≤ c ↔ ∀ o' < o, aleph' o' ≤ c
⟨λ h o' h', (aleph'_le.2 $ h'.le).trans h, λ h, begin rw [←aleph'_aleph_idx c, aleph'_le, limit_le l], intros x h', rw [←aleph'_le, aleph'_aleph_idx], exact h _ h' end⟩
theorem
cardinal.aleph'_le_of_limit
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph'_limit {o : ordinal} (ho : o.is_limit) : aleph' o = ⨆ a : Iio o, aleph' a
begin refine le_antisymm _ (csupr_le' (λ i, aleph'_le.2 (le_of_lt i.2))), rw aleph'_le_of_limit ho, exact λ a ha, le_csupr (bdd_above_of_small _) (⟨a, ha⟩ : Iio o) end
theorem
cardinal.aleph'_limit
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "csupr_le'", "le_csupr", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph'_omega : aleph' ω = ℵ₀
eq_of_forall_ge_iff $ λ c, begin simp only [aleph'_le_of_limit omega_is_limit, lt_omega, exists_imp_distrib, aleph_0_le], exact forall_swap.trans (forall_congr $ λ n, by simp only [forall_eq, aleph'_nat]), end
theorem
cardinal.aleph'_omega
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "eq_of_forall_ge_iff", "exists_imp_distrib", "forall_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph'_equiv : ordinal ≃ cardinal
⟨aleph', aleph_idx, aleph_idx_aleph', aleph'_aleph_idx⟩
def
cardinal.aleph'_equiv
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "cardinal", "ordinal" ]
`aleph'` and `aleph_idx` form an equivalence between `ordinal` and `cardinal`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph (o : ordinal) : cardinal
aleph' (ω + o)
def
cardinal.aleph
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "cardinal", "ordinal" ]
The `aleph` function gives the infinite cardinals listed by their ordinal index. `aleph 0 = ℵ₀`, `aleph 1 = succ ℵ₀` is the first uncountable cardinal, and so on.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_lt {o₁ o₂ : ordinal} : aleph o₁ < aleph o₂ ↔ o₁ < o₂
aleph'_lt.trans (add_lt_add_iff_left _)
theorem
cardinal.aleph_lt
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_le {o₁ o₂ : ordinal} : aleph o₁ ≤ aleph o₂ ↔ o₁ ≤ o₂
le_iff_le_iff_lt_iff_lt.2 aleph_lt
theorem
cardinal.aleph_le
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
max_aleph_eq (o₁ o₂ : ordinal) : max (aleph o₁) (aleph o₂) = aleph (max o₁ o₂)
begin cases le_total (aleph o₁) (aleph o₂) with h h, { rw [max_eq_right h, max_eq_right (aleph_le.1 h)] }, { rw [max_eq_left h, max_eq_left (aleph_le.1 h)] } end
theorem
cardinal.max_aleph_eq
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_succ {o : ordinal} : aleph (succ o) = succ (aleph o)
by rw [aleph, add_succ, aleph'_succ, aleph]
theorem
cardinal.aleph_succ
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_zero : aleph 0 = ℵ₀
by rw [aleph, add_zero, aleph'_omega]
theorem
cardinal.aleph_zero
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_limit {o : ordinal} (ho : o.is_limit) : aleph o = ⨆ a : Iio o, aleph a
begin apply le_antisymm _ (csupr_le' _), { rw [aleph, aleph'_limit (ho.add _)], refine csupr_mono' (bdd_above_of_small _) _, rintro ⟨i, hi⟩, cases lt_or_le i ω, { rcases lt_omega.1 h with ⟨n, rfl⟩, use ⟨0, ho.pos⟩, simpa using (nat_lt_aleph_0 n).le }, { exact ⟨⟨_, (sub_lt_of_le h).2 ...
theorem
cardinal.aleph_limit
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "csupr_le'", "csupr_mono'", "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_0_le_aleph' {o : ordinal} : ℵ₀ ≤ aleph' o ↔ ω ≤ o
by rw [← aleph'_omega, aleph'_le]
theorem
cardinal.aleph_0_le_aleph'
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_0_le_aleph (o : ordinal) : ℵ₀ ≤ aleph o
by { rw [aleph, aleph_0_le_aleph'], apply ordinal.le_add_right }
theorem
cardinal.aleph_0_le_aleph
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal", "ordinal.le_add_right" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph'_pos {o : ordinal} (ho : 0 < o) : 0 < aleph' o
by rwa [←aleph'_zero, aleph'_lt]
theorem
cardinal.aleph'_pos
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_pos (o : ordinal) : 0 < aleph o
aleph_0_pos.trans_le (aleph_0_le_aleph o)
theorem
cardinal.aleph_pos
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_to_nat (o : ordinal) : (aleph o).to_nat = 0
to_nat_apply_of_aleph_0_le $ aleph_0_le_aleph o
theorem
cardinal.aleph_to_nat
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal", "to_nat" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_to_part_enat (o : ordinal) : (aleph o).to_part_enat = ⊤
to_part_enat_apply_of_aleph_0_le $ aleph_0_le_aleph o
theorem
cardinal.aleph_to_part_enat
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nonempty_out_aleph (o : ordinal) : nonempty (aleph o).ord.out.α
begin rw [out_nonempty_iff_ne_zero, ←ord_zero], exact λ h, (ord_injective h).not_gt (aleph_pos o) end
instance
cardinal.nonempty_out_aleph
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord_aleph_is_limit (o : ordinal) : (aleph o).ord.is_limit
ord_is_limit $ aleph_0_le_aleph _
theorem
cardinal.ord_aleph_is_limit
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_aleph {c : cardinal} : ℵ₀ ≤ c ↔ ∃ o, c = aleph o
⟨λ h, ⟨aleph_idx c - ω, by { rw [aleph, ordinal.add_sub_cancel_of_le, aleph'_aleph_idx], rwa [← aleph_0_le_aleph', aleph'_aleph_idx] }⟩, λ ⟨o, e⟩, e.symm ▸ aleph_0_le_aleph _⟩
theorem
cardinal.exists_aleph
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "cardinal", "ordinal.add_sub_cancel_of_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph'_is_normal : is_normal (ord ∘ aleph')
⟨λ o, ord_lt_ord.2 $ aleph'_lt.2 $ lt_succ o, λ o l a, by simp only [ord_le, aleph'_le_of_limit l]⟩
theorem
cardinal.aleph'_is_normal
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_is_normal : is_normal (ord ∘ aleph)
aleph'_is_normal.trans $ add_is_normal ω
theorem
cardinal.aleph_is_normal
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
succ_aleph_0 : succ ℵ₀ = aleph 1
by rw [←aleph_zero, ←aleph_succ, ordinal.succ_zero]
theorem
cardinal.succ_aleph_0
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal.succ_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_0_lt_aleph_one : ℵ₀ < aleph 1
by { rw ←succ_aleph_0, apply lt_succ }
lemma
cardinal.aleph_0_lt_aleph_one
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
countable_iff_lt_aleph_one {α : Type*} (s : set α) : s.countable ↔ #s < aleph 1
by rw [←succ_aleph_0, lt_succ_iff, le_aleph_0_iff_set_countable]
lemma
cardinal.countable_iff_lt_aleph_one
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord_card_unbounded : unbounded (<) {b : ordinal | b.card.ord = b}
unbounded_lt_iff.2 $ λ a, ⟨_, ⟨(by { dsimp, rw card_ord }), (lt_ord_succ_card a).le⟩⟩
theorem
cardinal.ord_card_unbounded
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal" ]
Ordinals that are cardinals are unbounded.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_aleph'_of_eq_card_ord {o : ordinal} (ho : o.card.ord = o) : ∃ a, (aleph' a).ord = o
⟨cardinal.aleph_idx.rel_iso o.card, by simpa using ho⟩
theorem
cardinal.eq_aleph'_of_eq_card_ord
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord_aleph'_eq_enum_card : ord ∘ aleph' = enum_ord {b : ordinal | b.card.ord = b}
begin rw [←eq_enum_ord _ ord_card_unbounded, range_eq_iff], exact ⟨aleph'_is_normal.strict_mono, ⟨(λ a, (by { dsimp, rw card_ord })), λ b hb, eq_aleph'_of_eq_card_ord hb⟩⟩ end
theorem
cardinal.ord_aleph'_eq_enum_card
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal" ]
`ord ∘ aleph'` enumerates the ordinals that are cardinals.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ord_card_unbounded' : unbounded (<) {b : ordinal | b.card.ord = b ∧ ω ≤ b}
(unbounded_lt_inter_le ω).2 ord_card_unbounded
theorem
cardinal.ord_card_unbounded'
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal" ]
Infinite ordinals that are cardinals are unbounded.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_aleph_of_eq_card_ord {o : ordinal} (ho : o.card.ord = o) (ho' : ω ≤ o) : ∃ a, (aleph a).ord = o
begin cases eq_aleph'_of_eq_card_ord ho with a ha, use a - ω, unfold aleph, rwa ordinal.add_sub_cancel_of_le, rwa [←aleph_0_le_aleph', ←ord_le_ord, ha, ord_aleph_0] end
theorem
cardinal.eq_aleph_of_eq_card_ord
set_theory.cardinal
src/set_theory/cardinal/ordinal.lean
[ "data.finsupp.multiset", "order.bounded", "set_theory.ordinal.principal", "tactic.linarith" ]
[ "ordinal", "ordinal.add_sub_cancel_of_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83