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nsmul_lt_aleph_0_iff_of_ne_zero {n : ℕ} {a : cardinal} (h : n ≠ 0) : n • a < ℵ₀ ↔ a < ℵ₀
nsmul_lt_aleph_0_iff.trans $ or_iff_right h
lemma
cardinal.nsmul_lt_aleph_0_iff_of_ne_zero
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal", "or_iff_right" ]
See also `cardinal.nsmul_lt_aleph_0_iff` for a hypothesis-free version.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_lt_aleph_0 {a b : cardinal} (ha : a < ℵ₀) (hb : b < ℵ₀) : a * b < ℵ₀
match a, b, lt_aleph_0.1 ha, lt_aleph_0.1 hb with | _, _, ⟨m, rfl⟩, ⟨n, rfl⟩ := by rw [← nat.cast_mul]; apply nat_lt_aleph_0 end
theorem
cardinal.mul_lt_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal", "nat.cast_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_lt_aleph_0_iff {a b : cardinal} : a * b < ℵ₀ ↔ a = 0 ∨ b = 0 ∨ a < ℵ₀ ∧ b < ℵ₀
begin refine ⟨λ h, _, _⟩, { by_cases ha : a = 0, { exact or.inl ha }, right, by_cases hb : b = 0, { exact or.inl hb }, right, rw [←ne, ←one_le_iff_ne_zero] at ha hb, split, { rw ←mul_one a, refine (mul_le_mul' le_rfl hb).trans_lt h }, { rw ←one_mul b, refine (mul_le_mul' ha le_rfl).trans...
lemma
cardinal.mul_lt_aleph_0_iff
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal", "le_rfl", "mul_le_mul'", "mul_zero", "zero_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_0_le_mul_iff {a b : cardinal} : ℵ₀ ≤ a * b ↔ a ≠ 0 ∧ b ≠ 0 ∧ (ℵ₀ ≤ a ∨ ℵ₀ ≤ b)
let h := (@mul_lt_aleph_0_iff a b).not in by rwa [not_lt, not_or_distrib, not_or_distrib, not_and_distrib, not_lt, not_lt] at h
lemma
cardinal.aleph_0_le_mul_iff
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal", "not_and_distrib", "not_or_distrib" ]
See also `cardinal.aleph_0_le_mul_iff`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_0_le_mul_iff' {a b : cardinal.{u}} : ℵ₀ ≤ a * b ↔ a ≠ 0 ∧ ℵ₀ ≤ b ∨ ℵ₀ ≤ a ∧ b ≠ 0
begin have : ∀ {a : cardinal.{u}}, ℵ₀ ≤ a → a ≠ 0, from λ a, ne_bot_of_le_ne_bot aleph_0_ne_zero, simp only [aleph_0_le_mul_iff, and_or_distrib_left, and_iff_right_of_imp this, @and.left_comm (a ≠ 0)], simp only [and.comm, or.comm] end
lemma
cardinal.aleph_0_le_mul_iff'
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "and_iff_right_of_imp", "and_or_distrib_left", "ne_bot_of_le_ne_bot" ]
See also `cardinal.aleph_0_le_mul_iff'`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_lt_aleph_0_iff_of_ne_zero {a b : cardinal} (ha : a ≠ 0) (hb : b ≠ 0) : a * b < ℵ₀ ↔ a < ℵ₀ ∧ b < ℵ₀
by simp [mul_lt_aleph_0_iff, ha, hb]
lemma
cardinal.mul_lt_aleph_0_iff_of_ne_zero
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
power_lt_aleph_0 {a b : cardinal} (ha : a < ℵ₀) (hb : b < ℵ₀) : a ^ b < ℵ₀
match a, b, lt_aleph_0.1 ha, lt_aleph_0.1 hb with | _, _, ⟨m, rfl⟩, ⟨n, rfl⟩ := by rw [← nat_cast_pow]; apply nat_lt_aleph_0 end
theorem
cardinal.power_lt_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_one_iff_unique {α : Type*} : #α = 1 ↔ subsingleton α ∧ nonempty α
calc #α = 1 ↔ #α ≤ 1 ∧ 1 ≤ #α : le_antisymm_iff ... ↔ subsingleton α ∧ nonempty α : le_one_iff_subsingleton.and (one_le_iff_ne_zero.trans mk_ne_zero_iff)
lemma
cardinal.eq_one_iff_unique
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
infinite_iff {α : Type u} : infinite α ↔ ℵ₀ ≤ #α
by rw [← not_lt, lt_aleph_0_iff_finite, not_finite_iff_infinite]
theorem
cardinal.infinite_iff
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "infinite", "not_finite_iff_infinite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_0_le_mk (α : Type u) [infinite α] : ℵ₀ ≤ #α
infinite_iff.1 ‹_›
lemma
cardinal.aleph_0_le_mk
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "infinite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_eq_aleph_0 (α : Type*) [countable α] [infinite α] : #α = ℵ₀
mk_le_aleph_0.antisymm $ aleph_0_le_mk _
lemma
cardinal.mk_eq_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "countable", "infinite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
denumerable_iff {α : Type u} : nonempty (denumerable α) ↔ #α = ℵ₀
⟨λ ⟨h⟩, mk_congr ((@denumerable.eqv α h).trans equiv.ulift.symm), λ h, by { cases quotient.exact h with f, exact ⟨denumerable.mk' $ f.trans equiv.ulift⟩ }⟩
lemma
cardinal.denumerable_iff
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "denumerable", "denumerable.eqv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_denumerable (α : Type u) [denumerable α] : #α = ℵ₀
denumerable_iff.1 ⟨‹_›⟩
lemma
cardinal.mk_denumerable
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "denumerable" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_0_add_aleph_0 : ℵ₀ + ℵ₀ = ℵ₀
mk_denumerable _
lemma
cardinal.aleph_0_add_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_0_mul_aleph_0 : ℵ₀ * ℵ₀ = ℵ₀
mk_denumerable _
lemma
cardinal.aleph_0_mul_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_mul_aleph_0 {n : ℕ} (hn : n ≠ 0) : ↑n * ℵ₀ = ℵ₀
le_antisymm (lift_mk_fin n ▸ mk_le_aleph_0) $ le_mul_of_one_le_left (zero_le _) $ by rwa [← nat.cast_one, nat_cast_le, nat.one_le_iff_ne_zero]
lemma
cardinal.nat_mul_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "le_mul_of_one_le_left", "nat.cast_one", "nat.one_le_iff_ne_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_0_mul_nat {n : ℕ} (hn : n ≠ 0) : ℵ₀ * n = ℵ₀
by rw [mul_comm, nat_mul_aleph_0 hn]
lemma
cardinal.aleph_0_mul_nat
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "mul_comm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_le_aleph_0 {c₁ c₂ : cardinal} : c₁ + c₂ ≤ ℵ₀ ↔ c₁ ≤ ℵ₀ ∧ c₂ ≤ ℵ₀
⟨λ h, ⟨le_self_add.trans h, le_add_self.trans h⟩, λ h, aleph_0_add_aleph_0 ▸ add_le_add h.1 h.2⟩
lemma
cardinal.add_le_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_0_add_nat (n : ℕ) : ℵ₀ + n = ℵ₀
(add_le_aleph_0.2 ⟨le_rfl, (nat_lt_aleph_0 n).le⟩).antisymm le_self_add
lemma
cardinal.aleph_0_add_nat
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_add_aleph_0 (n : ℕ) : ↑n + ℵ₀ = ℵ₀
by rw [add_comm, aleph_0_add_nat]
lemma
cardinal.nat_add_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_nat : zero_hom cardinal ℕ
⟨λ c, if h : c < aleph_0.{v} then classical.some (lt_aleph_0.1 h) else 0, begin have h : 0 < ℵ₀ := nat_lt_aleph_0 0, rw [dif_pos h, ← cardinal.nat_cast_inj, ← classical.some_spec (lt_aleph_0.1 h), nat.cast_zero], end⟩
def
cardinal.to_nat
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal", "cardinal.nat_cast_inj", "nat.cast_zero", "to_nat", "zero_hom" ]
This function sends finite cardinals to the corresponding natural, and infinite cardinals to 0.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_nat_apply_of_lt_aleph_0 {c : cardinal} (h : c < ℵ₀) : c.to_nat = classical.some (lt_aleph_0.1 h)
dif_pos h
lemma
cardinal.to_nat_apply_of_lt_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_nat_apply_of_aleph_0_le {c : cardinal} (h : ℵ₀ ≤ c) : c.to_nat = 0
dif_neg h.not_lt
lemma
cardinal.to_nat_apply_of_aleph_0_le
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cast_to_nat_of_lt_aleph_0 {c : cardinal} (h : c < ℵ₀) : ↑c.to_nat = c
by rw [to_nat_apply_of_lt_aleph_0 h, ← classical.some_spec (lt_aleph_0.1 h)]
lemma
cardinal.cast_to_nat_of_lt_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cast_to_nat_of_aleph_0_le {c : cardinal} (h : ℵ₀ ≤ c) : ↑c.to_nat = (0 : cardinal)
by rw [to_nat_apply_of_aleph_0_le h, nat.cast_zero]
lemma
cardinal.cast_to_nat_of_aleph_0_le
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal", "nat.cast_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_nat_eq_iff_eq_of_lt_aleph_0 {c d : cardinal} (hc : c < ℵ₀) (hd : d < ℵ₀) : c.to_nat = d.to_nat ↔ c = d
by rw [←nat_cast_inj, cast_to_nat_of_lt_aleph_0 hc, cast_to_nat_of_lt_aleph_0 hd]
lemma
cardinal.to_nat_eq_iff_eq_of_lt_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_nat_le_iff_le_of_lt_aleph_0 {c d : cardinal} (hc : c < ℵ₀) (hd : d < ℵ₀) : c.to_nat ≤ d.to_nat ↔ c ≤ d
by rw [←nat_cast_le, cast_to_nat_of_lt_aleph_0 hc, cast_to_nat_of_lt_aleph_0 hd]
lemma
cardinal.to_nat_le_iff_le_of_lt_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_nat_lt_iff_lt_of_lt_aleph_0 {c d : cardinal} (hc : c < ℵ₀) (hd : d < ℵ₀) : c.to_nat < d.to_nat ↔ c < d
by rw [←nat_cast_lt, cast_to_nat_of_lt_aleph_0 hc, cast_to_nat_of_lt_aleph_0 hd]
lemma
cardinal.to_nat_lt_iff_lt_of_lt_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_nat_le_of_le_of_lt_aleph_0 {c d : cardinal} (hd : d < ℵ₀) (hcd : c ≤ d) : c.to_nat ≤ d.to_nat
(to_nat_le_iff_le_of_lt_aleph_0 (hcd.trans_lt hd) hd).mpr hcd
lemma
cardinal.to_nat_le_of_le_of_lt_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_nat_lt_of_lt_of_lt_aleph_0 {c d : cardinal} (hd : d < ℵ₀) (hcd : c < d) : c.to_nat < d.to_nat
(to_nat_lt_iff_lt_of_lt_aleph_0 (hcd.trans hd) hd).mpr hcd
lemma
cardinal.to_nat_lt_of_lt_of_lt_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_nat_cast (n : ℕ) : cardinal.to_nat n = n
begin rw [to_nat_apply_of_lt_aleph_0 (nat_lt_aleph_0 n), ← nat_cast_inj], exact (classical.some_spec (lt_aleph_0.1 (nat_lt_aleph_0 n))).symm, end
lemma
cardinal.to_nat_cast
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal.to_nat" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_nat_right_inverse : function.right_inverse (coe : ℕ → cardinal) to_nat
to_nat_cast
lemma
cardinal.to_nat_right_inverse
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal", "to_nat" ]
`to_nat` has a right-inverse: coercion.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_nat_surjective : surjective to_nat
to_nat_right_inverse.surjective
lemma
cardinal.to_nat_surjective
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "to_nat" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_nat_eq_of_le_nat {c : cardinal} {n : ℕ} (h : c ≤ n) : ∃ m, m ≤ n ∧ c = m
let he := cast_to_nat_of_lt_aleph_0 (h.trans_lt $ nat_lt_aleph_0 n) in ⟨c.to_nat, nat_cast_le.1 (he.trans_le h), he.symm⟩
lemma
cardinal.exists_nat_eq_of_le_nat
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_to_nat_of_infinite [h : infinite α] : (#α).to_nat = 0
dif_neg (infinite_iff.1 h).not_lt
lemma
cardinal.mk_to_nat_of_infinite
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "infinite", "to_nat" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_0_to_nat : to_nat ℵ₀ = 0
to_nat_apply_of_aleph_0_le le_rfl
theorem
cardinal.aleph_0_to_nat
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "le_rfl", "to_nat" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_to_nat_eq_card [fintype α] : (#α).to_nat = fintype.card α
by simp
lemma
cardinal.mk_to_nat_eq_card
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "fintype", "fintype.card", "to_nat" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
zero_to_nat : to_nat 0 = 0
by rw [←to_nat_cast 0, nat.cast_zero]
lemma
cardinal.zero_to_nat
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "nat.cast_zero", "to_nat" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one_to_nat : to_nat 1 = 1
by rw [←to_nat_cast 1, nat.cast_one]
lemma
cardinal.one_to_nat
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "nat.cast_one", "to_nat" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_nat_eq_iff {c : cardinal} {n : ℕ} (hn : n ≠ 0) : to_nat c = n ↔ c = n
⟨λ h, (cast_to_nat_of_lt_aleph_0 (lt_of_not_ge (hn ∘ h.symm.trans ∘ to_nat_apply_of_aleph_0_le))).symm.trans (congr_arg coe h), λ h, (congr_arg to_nat h).trans (to_nat_cast n)⟩
lemma
cardinal.to_nat_eq_iff
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal", "to_nat" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_nat_eq_one {c : cardinal} : to_nat c = 1 ↔ c = 1
by rw [to_nat_eq_iff one_ne_zero, nat.cast_one]
lemma
cardinal.to_nat_eq_one
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal", "nat.cast_one", "one_ne_zero", "to_nat" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_nat_eq_one_iff_unique {α : Type*} : (#α).to_nat = 1 ↔ subsingleton α ∧ nonempty α
to_nat_eq_one.trans eq_one_iff_unique
lemma
cardinal.to_nat_eq_one_iff_unique
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "to_nat" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_nat_lift (c : cardinal.{v}) : (lift.{u v} c).to_nat = c.to_nat
begin apply nat_cast_injective, cases lt_or_ge c ℵ₀ with hc hc, { rw [cast_to_nat_of_lt_aleph_0, ←lift_nat_cast, cast_to_nat_of_lt_aleph_0 hc], rwa [lift_lt_aleph_0] }, { rw [cast_to_nat_of_aleph_0_le, ←lift_nat_cast, cast_to_nat_of_aleph_0_le hc, lift_zero], rwa [aleph_0_le_lift] }, end
lemma
cardinal.to_nat_lift
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "to_nat" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_nat_congr {β : Type v} (e : α ≃ β) : (#α).to_nat = (#β).to_nat
by rw [←to_nat_lift, lift_mk_eq.mpr ⟨e⟩, to_nat_lift]
lemma
cardinal.to_nat_congr
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "to_nat" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_nat_mul (x y : cardinal) : (x * y).to_nat = x.to_nat * y.to_nat
begin rcases eq_or_ne x 0 with rfl | hx1, { rw [zero_mul, zero_to_nat, zero_mul] }, rcases eq_or_ne y 0 with rfl | hy1, { rw [mul_zero, zero_to_nat, mul_zero] }, cases lt_or_le x ℵ₀ with hx2 hx2, { cases lt_or_le y ℵ₀ with hy2 hy2, { lift x to ℕ using hx2, lift y to ℕ using hy2, rw [← nat.cast_mul...
lemma
cardinal.to_nat_mul
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal", "eq_or_ne", "lift", "mul_zero", "nat.cast_mul", "to_nat", "zero_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_nat_hom : cardinal →*₀ ℕ
{ to_fun := to_nat, map_zero' := zero_to_nat, map_one' := one_to_nat, map_mul' := to_nat_mul }
def
cardinal.to_nat_hom
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal", "to_nat" ]
`cardinal.to_nat` as a `monoid_with_zero_hom`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_nat_finset_prod (s : finset α) (f : α → cardinal) : to_nat (∏ i in s, f i) = ∏ i in s, to_nat (f i)
map_prod to_nat_hom _ _
lemma
cardinal.to_nat_finset_prod
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal", "finset", "map_prod", "to_nat" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_nat_add_of_lt_aleph_0 {a : cardinal.{u}} {b : cardinal.{v}} (ha : a < ℵ₀) (hb : b < ℵ₀) : ((lift.{v u} a) + (lift.{u v} b)).to_nat = a.to_nat + b.to_nat
begin apply cardinal.nat_cast_injective, replace ha : (lift.{v u} a) < ℵ₀ := by rwa lift_lt_aleph_0, replace hb : (lift.{u v} b) < ℵ₀ := by rwa lift_lt_aleph_0, rw [nat.cast_add, ←to_nat_lift.{v u} a, ←to_nat_lift.{u v} b, cast_to_nat_of_lt_aleph_0 ha, cast_to_nat_of_lt_aleph_0 hb, cast_to_nat_of_lt_aleph_0...
lemma
cardinal.to_nat_add_of_lt_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal.nat_cast_injective", "nat.cast_add", "to_nat" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_part_enat : cardinal →+ part_enat
{ to_fun := λ c, if c < ℵ₀ then c.to_nat else ⊤, map_zero' := by simp [if_pos (zero_lt_one.trans one_lt_aleph_0)], map_add' := λ x y, begin by_cases hx : x < ℵ₀, { obtain ⟨x0, rfl⟩ := lt_aleph_0.1 hx, by_cases hy : y < ℵ₀, { obtain ⟨y0, rfl⟩ := lt_aleph_0.1 hy, simp only [add_lt_aleph_0 ...
def
cardinal.to_part_enat
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal", "nat.cast_add", "part_enat", "part_enat.add_top", "part_enat.top_add" ]
This function sends finite cardinals to the corresponding natural, and infinite cardinals to `⊤`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_part_enat_apply_of_lt_aleph_0 {c : cardinal} (h : c < ℵ₀) : c.to_part_enat = c.to_nat
if_pos h
lemma
cardinal.to_part_enat_apply_of_lt_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_part_enat_apply_of_aleph_0_le {c : cardinal} (h : ℵ₀ ≤ c) : c.to_part_enat = ⊤
if_neg h.not_lt
lemma
cardinal.to_part_enat_apply_of_aleph_0_le
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_part_enat_cast (n : ℕ) : cardinal.to_part_enat n = n
by rw [to_part_enat_apply_of_lt_aleph_0 (nat_lt_aleph_0 n), to_nat_cast]
lemma
cardinal.to_part_enat_cast
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal.to_part_enat" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_to_part_enat_of_infinite [h : infinite α] : (#α).to_part_enat = ⊤
to_part_enat_apply_of_aleph_0_le (infinite_iff.1 h)
lemma
cardinal.mk_to_part_enat_of_infinite
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "infinite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aleph_0_to_part_enat : to_part_enat ℵ₀ = ⊤
to_part_enat_apply_of_aleph_0_le le_rfl
theorem
cardinal.aleph_0_to_part_enat
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "le_rfl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_part_enat_eq_top_iff_le_aleph_0 {c : cardinal} : to_part_enat c = ⊤ ↔ aleph_0 ≤ c
begin cases lt_or_ge c aleph_0 with hc hc, simp only [to_part_enat_apply_of_lt_aleph_0 hc, part_enat.coe_ne_top, false_iff, not_le, hc], simp only [to_part_enat_apply_of_aleph_0_le hc, eq_self_iff_true, true_iff], exact hc, end
lemma
cardinal.to_part_enat_eq_top_iff_le_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal", "part_enat.coe_ne_top" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_part_enat_le_iff_le_of_le_aleph_0 {c c' : cardinal} (h : c ≤ aleph_0) : to_part_enat c ≤ to_part_enat c' ↔ c ≤ c'
begin cases lt_or_ge c aleph_0 with hc hc, rw to_part_enat_apply_of_lt_aleph_0 hc, cases lt_or_ge c' aleph_0 with hc' hc', { rw to_part_enat_apply_of_lt_aleph_0 hc', rw part_enat.coe_le_coe, exact to_nat_le_iff_le_of_lt_aleph_0 hc hc', }, { simp only [to_part_enat_apply_of_aleph_0_le hc', le_top, ...
lemma
cardinal.to_part_enat_le_iff_le_of_le_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal", "le_top", "part_enat.coe_le_coe", "top_le_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_part_enat_le_iff_le_of_lt_aleph_0 {c c' : cardinal} (hc' : c' < aleph_0) : to_part_enat c ≤ to_part_enat c' ↔ c ≤ c'
begin cases lt_or_ge c aleph_0 with hc hc, { rw to_part_enat_apply_of_lt_aleph_0 hc, rw to_part_enat_apply_of_lt_aleph_0 hc', rw part_enat.coe_le_coe, exact to_nat_le_iff_le_of_lt_aleph_0 hc hc', }, { rw to_part_enat_apply_of_aleph_0_le hc, simp only [top_le_iff, to_part_enat_eq_top_iff_le_aleph_0...
lemma
cardinal.to_part_enat_le_iff_le_of_lt_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal", "not_iff_not", "part_enat.coe_le_coe", "top_le_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_part_enat_eq_iff_eq_of_le_aleph_0 {c c' : cardinal} (hc : c ≤ aleph_0) (hc' : c' ≤ aleph_0) : to_part_enat c = to_part_enat c' ↔ c = c'
by rw [le_antisymm_iff, le_antisymm_iff, to_part_enat_le_iff_le_of_le_aleph_0 hc, to_part_enat_le_iff_le_of_le_aleph_0 hc']
lemma
cardinal.to_part_enat_eq_iff_eq_of_le_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_part_enat_mono {c c' : cardinal} (h : c ≤ c') : to_part_enat c ≤ to_part_enat c'
begin cases lt_or_ge c aleph_0 with hc hc, rw to_part_enat_apply_of_lt_aleph_0 hc, cases lt_or_ge c' aleph_0 with hc' hc', rw to_part_enat_apply_of_lt_aleph_0 hc', simp only [part_enat.coe_le_coe], exact to_nat_le_of_le_of_lt_aleph_0 hc' h, rw to_part_enat_apply_of_aleph_0_le hc', exact le_top, rw [to...
lemma
cardinal.to_part_enat_mono
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal", "le_top", "part_enat.coe_le_coe" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_part_enat_surjective : surjective to_part_enat
λ x, part_enat.cases_on x ⟨ℵ₀, to_part_enat_apply_of_aleph_0_le le_rfl⟩ $ λ n, ⟨n, to_part_enat_cast n⟩
lemma
cardinal.to_part_enat_surjective
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "part_enat.cases_on" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_part_enat_lift (c : cardinal.{v}) : (lift.{u v} c).to_part_enat = c.to_part_enat
begin cases lt_or_ge c ℵ₀ with hc hc, { rw [to_part_enat_apply_of_lt_aleph_0 hc, cardinal.to_part_enat_apply_of_lt_aleph_0 _], simp only [to_nat_lift], rw [← lift_aleph_0, lift_lt], exact hc }, { rw [to_part_enat_apply_of_aleph_0_le hc, cardinal.to_part_enat_apply_of_aleph_0_le _], rw [← lift_aleph_0, l...
lemma
cardinal.to_part_enat_lift
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal.to_part_enat_apply_of_aleph_0_le", "cardinal.to_part_enat_apply_of_lt_aleph_0" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_part_enat_congr {β : Type v} (e : α ≃ β) : (#α).to_part_enat = (#β).to_part_enat
by rw [←to_part_enat_lift, lift_mk_eq.mpr ⟨e⟩, to_part_enat_lift]
lemma
cardinal.to_part_enat_congr
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_to_part_enat_eq_coe_card [fintype α] : (#α).to_part_enat = fintype.card α
by simp
lemma
cardinal.mk_to_part_enat_eq_coe_card
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "fintype", "fintype.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_int : #ℤ = ℵ₀
mk_denumerable ℤ
lemma
cardinal.mk_int
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_pnat : #ℕ+ = ℵ₀
mk_denumerable ℕ+
lemma
cardinal.mk_pnat
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sum_lt_prod {ι} (f g : ι → cardinal) (H : ∀ i, f i < g i) : sum f < prod g
lt_of_not_ge $ λ ⟨F⟩, begin haveI : inhabited (Π (i : ι), (g i).out), { refine ⟨λ i, classical.choice $ mk_ne_zero_iff.1 _⟩, rw mk_out, exact (H i).ne_bot }, let G := inv_fun F, have sG : surjective G := inv_fun_surjective F.2, choose C hc using show ∀ i, ∃ b, ∀ a, G ⟨i, a⟩ i ≠ b, { intro i, sim...
theorem
cardinal.sum_lt_prod
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "cardinal", "inv_fun", "inv_fun_surjective", "not_exists" ]
**König's theorem**
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_empty : #empty = 0
mk_eq_zero _
theorem
cardinal.mk_empty
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_pempty : #pempty = 0
mk_eq_zero _
theorem
cardinal.mk_pempty
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "pempty" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_punit : #punit = 1
mk_eq_one punit
theorem
cardinal.mk_punit
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_unit : #unit = 1
mk_punit
theorem
cardinal.mk_unit
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_singleton {α : Type u} (x : α) : #({x} : set α) = 1
mk_eq_one _
theorem
cardinal.mk_singleton
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_plift_true : #(plift true) = 1
mk_eq_one _
theorem
cardinal.mk_plift_true
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_plift_false : #(plift false) = 0
mk_eq_zero _
theorem
cardinal.mk_plift_false
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_vector (α : Type u) (n : ℕ) : #(vector α n) = (#α) ^ℕ n
(mk_congr (equiv.vector_equiv_fin α n)).trans $ by simp
theorem
cardinal.mk_vector
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "equiv.vector_equiv_fin" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_list_eq_sum_pow (α : Type u) : #(list α) = sum (λ n : ℕ, (#α) ^ℕ n)
calc #(list α) = #(Σ n, vector α n) : mk_congr (equiv.sigma_fiber_equiv list.length).symm ... = sum (λ n : ℕ, (#α) ^ℕ n) : by simp
theorem
cardinal.mk_list_eq_sum_pow
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "equiv.sigma_fiber_equiv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_quot_le {α : Type u} {r : α → α → Prop} : #(quot r) ≤ #α
mk_le_of_surjective quot.exists_rep
theorem
cardinal.mk_quot_le
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_quotient_le {α : Type u} {s : setoid α} : #(quotient s) ≤ #α
mk_quot_le
theorem
cardinal.mk_quotient_le
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_subtype_le_of_subset {α : Type u} {p q : α → Prop} (h : ∀ ⦃x⦄, p x → q x) : #(subtype p) ≤ #(subtype q)
⟨embedding.subtype_map (embedding.refl α) h⟩
theorem
cardinal.mk_subtype_le_of_subset
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_emptyc (α : Type u) : #(∅ : set α) = 0
mk_eq_zero _
theorem
cardinal.mk_emptyc
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_emptyc_iff {α : Type u} {s : set α} : #s = 0 ↔ s = ∅
begin split, { intro h, rw mk_eq_zero_iff at h, exact eq_empty_iff_forall_not_mem.2 (λ x hx, h.elim' ⟨x, hx⟩) }, { rintro rfl, exact mk_emptyc _ } end
lemma
cardinal.mk_emptyc_iff
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_univ {α : Type u} : #(@univ α) = #α
mk_congr (equiv.set.univ α)
theorem
cardinal.mk_univ
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "equiv.set.univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_image_le {α β : Type u} {f : α → β} {s : set α} : #(f '' s) ≤ #s
mk_le_of_surjective surjective_onto_image
theorem
cardinal.mk_image_le
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_image_le_lift {α : Type u} {β : Type v} {f : α → β} {s : set α} : lift.{u} (#(f '' s)) ≤ lift.{v} (#s)
lift_mk_le.{v u 0}.mpr ⟨embedding.of_surjective _ surjective_onto_image⟩
theorem
cardinal.mk_image_le_lift
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_range_le {α β : Type u} {f : α → β} : #(range f) ≤ #α
mk_le_of_surjective surjective_onto_range
theorem
cardinal.mk_range_le
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_range_le_lift {α : Type u} {β : Type v} {f : α → β} : lift.{u} (#(range f)) ≤ lift.{v} (#α)
lift_mk_le.{v u 0}.mpr ⟨embedding.of_surjective _ surjective_onto_range⟩
theorem
cardinal.mk_range_le_lift
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_range_eq (f : α → β) (h : injective f) : #(range f) = #α
mk_congr ((equiv.of_injective f h).symm)
lemma
cardinal.mk_range_eq
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "equiv.of_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_range_eq_of_injective {α : Type u} {β : Type v} {f : α → β} (hf : injective f) : lift.{u} (#(range f)) = lift.{v} (#α)
lift_mk_eq'.mpr ⟨(equiv.of_injective f hf).symm⟩
lemma
cardinal.mk_range_eq_of_injective
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "equiv.of_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_range_eq_lift {α : Type u} {β : Type v} {f : α → β} (hf : injective f) : lift.{max u w} (# (range f)) = lift.{max v w} (# α)
lift_mk_eq.mpr ⟨(equiv.of_injective f hf).symm⟩
lemma
cardinal.mk_range_eq_lift
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "equiv.of_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_image_eq {α β : Type u} {f : α → β} {s : set α} (hf : injective f) : #(f '' s) = #s
mk_congr ((equiv.set.image f s hf).symm)
theorem
cardinal.mk_image_eq
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "equiv.set.image" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_Union_le_sum_mk {α ι : Type u} {f : ι → set α} : #(⋃ i, f i) ≤ sum (λ i, #(f i))
calc #(⋃ i, f i) ≤ #(Σ i, f i) : mk_le_of_surjective (set.sigma_to_Union_surjective f) ... = sum (λ i, #(f i)) : mk_sigma _
theorem
cardinal.mk_Union_le_sum_mk
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "set.sigma_to_Union_surjective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_Union_eq_sum_mk {α ι : Type u} {f : ι → set α} (h : ∀i j, i ≠ j → disjoint (f i) (f j)) : #(⋃ i, f i) = sum (λ i, #(f i))
calc #(⋃ i, f i) = #(Σ i, f i) : mk_congr (set.Union_eq_sigma_of_disjoint h) ... = sum (λi, #(f i)) : mk_sigma _
theorem
cardinal.mk_Union_eq_sum_mk
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "disjoint", "set.Union_eq_sigma_of_disjoint" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_Union_le {α ι : Type u} (f : ι → set α) : #(⋃ i, f i) ≤ #ι * ⨆ i, #(f i)
mk_Union_le_sum_mk.trans (sum_le_supr _)
lemma
cardinal.mk_Union_le
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_sUnion_le {α : Type u} (A : set (set α)) : #(⋃₀ A) ≤ #A * ⨆ s : A, #s
by { rw sUnion_eq_Union, apply mk_Union_le }
lemma
cardinal.mk_sUnion_le
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_bUnion_le {ι α : Type u} (A : ι → set α) (s : set ι) : #(⋃ x ∈ s, A x) ≤ #s * ⨆ x : s, #(A x.1)
by { rw bUnion_eq_Union, apply mk_Union_le }
lemma
cardinal.mk_bUnion_le
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finset_card_lt_aleph_0 (s : finset α) : #(↑s : set α) < ℵ₀
lt_aleph_0_of_finite _
lemma
cardinal.finset_card_lt_aleph_0
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "finset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_set_eq_nat_iff_finset {α} {s : set α} {n : ℕ} : #s = n ↔ ∃ t : finset α, (t : set α) = s ∧ t.card = n
begin split, { intro h, lift s to finset α using lt_aleph_0_iff_set_finite.1 (h.symm ▸ nat_lt_aleph_0 n), simpa using h }, { rintro ⟨t, rfl, rfl⟩, exact mk_coe_finset } end
theorem
cardinal.mk_set_eq_nat_iff_finset
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "finset", "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_eq_nat_iff_finset {n : ℕ} : #α = n ↔ ∃ t : finset α, (t : set α) = univ ∧ t.card = n
by rw [← mk_univ, mk_set_eq_nat_iff_finset]
theorem
cardinal.mk_eq_nat_iff_finset
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "finset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_eq_nat_iff_fintype {n : ℕ} : #α = n ↔ ∃ (h : fintype α), @fintype.card α h = n
begin rw [mk_eq_nat_iff_finset], split, { rintro ⟨t, ht, hn⟩, exact ⟨⟨t, eq_univ_iff_forall.1 ht⟩, hn⟩ }, { rintro ⟨⟨t, ht⟩, hn⟩, exact ⟨t, eq_univ_iff_forall.2 ht, hn⟩ } end
theorem
cardinal.mk_eq_nat_iff_fintype
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[ "fintype", "fintype.card" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_union_add_mk_inter {α : Type u} {S T : set α} : #(S ∪ T : set α) + #(S ∩ T : set α) = #S + #T
quot.sound ⟨equiv.set.union_sum_inter S T⟩
theorem
cardinal.mk_union_add_mk_inter
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_union_le {α : Type u} (S T : set α) : #(S ∪ T : set α) ≤ #S + #T
@mk_union_add_mk_inter α S T ▸ self_le_add_right (#(S ∪ T : set α)) (#(S ∩ T : set α))
lemma
cardinal.mk_union_le
set_theory.cardinal
src/set_theory/cardinal/basic.lean
[ "data.fintype.big_operators", "data.finsupp.defs", "data.nat.part_enat", "data.set.countable", "logic.small.basic", "order.conditionally_complete_lattice.basic", "order.succ_pred.limit", "set_theory.cardinal.schroeder_bernstein", "tactic.positivity" ]
[]
The cardinality of a union is at most the sum of the cardinalities of the two sets.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83