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mk_eq (x : pSet) : @eq Set ⟦x⟧ (mk x)
rfl
theorem
Set.mk_eq
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set", "pSet" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_out : ∀ x : Set, mk x.out = x
quotient.out_eq
theorem
Set.mk_out
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set", "quotient.out_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq {x y : pSet} : mk x = mk y ↔ equiv x y
quotient.eq
theorem
Set.eq
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "equiv", "pSet", "quotient.eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sound {x y : pSet} (h : pSet.equiv x y) : mk x = mk y
quotient.sound h
theorem
Set.sound
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "pSet", "pSet.equiv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exact {x y : pSet} : mk x = mk y → pSet.equiv x y
quotient.exact
theorem
Set.exact
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "pSet", "pSet.equiv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eval_mk {n f x} : (@resp.eval (n+1) f : Set → arity Set n) (mk x) = resp.eval n (resp.f f x)
rfl
lemma
Set.eval_mk
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set", "arity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem : Set → Set → Prop
quotient.lift₂ pSet.mem (λ x y x' y' hx hy, propext ((mem.congr_left hx).trans (mem.congr_right hy)))
def
Set.mem
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set", "pSet.mem" ]
The membership relation for ZFC sets is inherited from the membership relation for pre-sets.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_mem_iff {x y : pSet} : mk x ∈ mk y ↔ x ∈ y
iff.rfl
theorem
Set.mk_mem_iff
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "pSet" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_set (u : Set.{u}) : set Set.{u}
{x | x ∈ u}
def
Set.to_set
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
Convert a ZFC set into a `set` of ZFC sets
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_to_set (a u : Set.{u}) : a ∈ u.to_set ↔ a ∈ u
iff.rfl
theorem
Set.mem_to_set
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
small_to_set (x : Set.{u}) : small.{u} x.to_set
quotient.induction_on x $ λ a, begin let f : a.type → (mk a).to_set := λ i, ⟨mk $ a.func i, func_mem a i⟩, suffices : function.surjective f, { exact small_of_surjective this }, rintro ⟨y, hb⟩, induction y using quotient.induction_on, cases hb with i h, exact ⟨i, subtype.coe_injective (quotient.sound h.sym...
instance
Set.small_to_set
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "small_of_surjective", "subtype.coe_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nonempty (u : Set) : Prop
u.to_set.nonempty
def
Set.nonempty
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
A nonempty set is one that contains some element.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nonempty_def (u : Set) : u.nonempty ↔ ∃ x, x ∈ u
iff.rfl
theorem
Set.nonempty_def
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nonempty_of_mem {x u : Set} (h : x ∈ u) : u.nonempty
⟨x, h⟩
theorem
Set.nonempty_of_mem
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nonempty_to_set_iff {u : Set} : u.to_set.nonempty ↔ u.nonempty
iff.rfl
theorem
Set.nonempty_to_set_iff
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
subset (x y : Set.{u})
∀ ⦃z⦄, z ∈ x → z ∈ y
def
Set.subset
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
`x ⊆ y` as ZFC sets means that all members of `x` are members of `y`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_subset : has_subset Set
⟨Set.subset⟩
instance
Set.has_subset
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
subset_def {x y : Set.{u}} : x ⊆ y ↔ ∀ ⦃z⦄, z ∈ x → z ∈ y
iff.rfl
lemma
Set.subset_def
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
subset_iff : Π {x y : pSet}, mk x ⊆ mk y ↔ x ⊆ y
| ⟨α, A⟩ ⟨β, B⟩ := ⟨λ h a, @h ⟦A a⟧ (mem.mk A a), λ h z, quotient.induction_on z (λ z ⟨a, za⟩, let ⟨b, ab⟩ := h a in ⟨b, za.trans ab⟩)⟩
theorem
Set.subset_iff
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "pSet" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_set_subset_iff {x y : Set} : x.to_set ⊆ y.to_set ↔ x ⊆ y
by simp [subset_def, set.subset_def]
theorem
Set.to_set_subset_iff
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set", "set.subset_def" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ext {x y : Set.{u}} : (∀ z : Set.{u}, z ∈ x ↔ z ∈ y) → x = y
quotient.induction_on₂ x y (λ u v h, quotient.sound (mem.ext (λ w, h ⟦w⟧)))
theorem
Set.ext
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ext_iff {x y : Set.{u}} : x = y ↔ (∀ z : Set.{u}, z ∈ x ↔ z ∈ y)
⟨λ h, by simp [h], ext⟩
theorem
Set.ext_iff
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_set_injective : function.injective to_set
λ x y h, ext $ set.ext_iff.1 h
theorem
Set.to_set_injective
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_set_inj {x y : Set} : x.to_set = y.to_set ↔ x = y
to_set_injective.eq_iff
theorem
Set.to_set_inj
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
empty : Set
mk ∅
def
Set.empty
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
The empty ZFC set
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
not_mem_empty (x) : x ∉ (∅ : Set.{u})
quotient.induction_on x pSet.not_mem_empty
theorem
Set.not_mem_empty
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "pSet.not_mem_empty" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
empty_subset (x : Set.{u}) : (∅ : Set) ⊆ x
quotient.induction_on x $ λ y, subset_iff.2 $ pSet.empty_subset y
theorem
Set.empty_subset
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set", "pSet.empty_subset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
not_nonempty_empty : ¬ Set.nonempty ∅
by simp [Set.nonempty]
theorem
Set.not_nonempty_empty
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set.nonempty" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nonempty_mk_iff {x : pSet} : (mk x).nonempty ↔ x.nonempty
begin refine ⟨_, λ ⟨a, h⟩, ⟨mk a, h⟩⟩, rintro ⟨a, h⟩, induction a using quotient.induction_on, exact ⟨a, h⟩ end
theorem
Set.nonempty_mk_iff
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "pSet" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_empty (x : Set.{u}) : x = ∅ ↔ ∀ y : Set.{u}, y ∉ x
by { rw ext_iff, simp }
theorem
Set.eq_empty
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_empty_or_nonempty (u : Set) : u = ∅ ∨ u.nonempty
by { rw [eq_empty, ←not_exists], apply em' }
theorem
Set.eq_empty_or_nonempty
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set", "em'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
insert : Set → Set → Set
resp.eval 2 ⟨pSet.insert, λ u v uv ⟨α, A⟩ ⟨β, B⟩ ⟨αβ, βα⟩, ⟨λ o, match o with | some a := let ⟨b, hb⟩ := αβ a in ⟨some b, hb⟩ | none := ⟨none, uv⟩ end, λ o, match o with | some b := let ⟨a, ha⟩ := βα b in ⟨some a, ha⟩ | none := ⟨none, uv⟩ end⟩⟩
def
Set.insert
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
`insert x y` is the set `{x} ∪ y`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_insert_iff {x y z : Set.{u}} : x ∈ insert y z ↔ x = y ∨ x ∈ z
quotient.induction_on₃ x y z (λ x y ⟨α, A⟩, show x ∈ pSet.mk (option α) (λ o, option.rec y A o) ↔ mk x = mk y ∨ x ∈ pSet.mk α A, from ⟨λ m, match m with | ⟨some a, ha⟩ := or.inr ⟨a, ha⟩ | ⟨none, h⟩ := or.inl (quotient.sound h) end, λ m, match m with | or.inr ⟨a, ha⟩ := ⟨some a, ha⟩ | or.inl h := ⟨none,...
theorem
Set.mem_insert_iff
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_insert (x y : Set) : x ∈ insert x y
mem_insert_iff.2 $ or.inl rfl
theorem
Set.mem_insert
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_insert_of_mem {y z : Set} (x) (h : z ∈ y): z ∈ insert x y
mem_insert_iff.2 $ or.inr h
theorem
Set.mem_insert_of_mem
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_set_insert (x y : Set) : (insert x y).to_set = insert x y.to_set
by { ext, simp }
theorem
Set.to_set_insert
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_singleton {x y : Set.{u}} : x ∈ @singleton Set.{u} Set.{u} _ y ↔ x = y
iff.trans mem_insert_iff ⟨λ o, or.rec (λ h, h) (λ n, absurd n (not_mem_empty _)) o, or.inl⟩
theorem
Set.mem_singleton
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_set_singleton (x : Set) : ({x} : Set).to_set = {x}
by { ext, simp }
theorem
Set.to_set_singleton
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
insert_nonempty (u v : Set) : (insert u v).nonempty
⟨u, mem_insert u v⟩
theorem
Set.insert_nonempty
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
singleton_nonempty (u : Set) : Set.nonempty {u}
insert_nonempty u ∅
theorem
Set.singleton_nonempty
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set", "Set.nonempty" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_pair {x y z : Set.{u}} : x ∈ ({y, z} : Set) ↔ x = y ∨ x = z
iff.trans mem_insert_iff $ or_congr iff.rfl mem_singleton
theorem
Set.mem_pair
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
omega : Set
mk omega
def
Set.omega
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
`omega` is the first infinite von Neumann ordinal
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
omega_zero : ∅ ∈ omega
⟨⟨0⟩, equiv.rfl⟩
theorem
Set.omega_zero
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
omega_succ {n} : n ∈ omega.{u} → insert n n ∈ omega.{u}
quotient.induction_on n (λ x ⟨⟨n⟩, h⟩, ⟨⟨n+1⟩, Set.exact $ show insert (mk x) (mk x) = insert (mk $ of_nat n) (mk $ of_nat n), { rw Set.sound h, refl } ⟩)
theorem
Set.omega_succ
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set.exact", "Set.sound" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sep (p : Set → Prop) : Set → Set
resp.eval 1 ⟨pSet.sep (λ y, p (mk y)), λ ⟨α, A⟩ ⟨β, B⟩ ⟨αβ, βα⟩, ⟨λ ⟨a, pa⟩, let ⟨b, hb⟩ := αβ a in ⟨⟨b, by rwa [mk_func, ←Set.sound hb]⟩, hb⟩, λ ⟨b, pb⟩, let ⟨a, ha⟩ := βα b in ⟨⟨a, by rwa [mk_func, Set.sound ha]⟩, ha⟩⟩⟩
def
Set.sep
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set", "Set.sound" ]
`{x ∈ a | p x}` is the set of elements in `a` satisfying `p`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_sep {p : Set.{u} → Prop} {x y : Set.{u}} : y ∈ {y ∈ x | p y} ↔ y ∈ x ∧ p y
quotient.induction_on₂ x y (λ ⟨α, A⟩ y, ⟨λ ⟨⟨a, pa⟩, h⟩, ⟨⟨a, h⟩, by rwa (@quotient.sound pSet _ _ _ h)⟩, λ ⟨⟨a, h⟩, pa⟩, ⟨⟨a, by { rw mk_func at h, rwa [mk_func, ←Set.sound h] }⟩, h⟩⟩)
theorem
Set.mem_sep
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "pSet" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_set_sep (a : Set) (p : Set → Prop) : {x ∈ a | p x}.to_set = {x ∈ a.to_set | p x}
by { ext, simp }
theorem
Set.to_set_sep
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
powerset : Set → Set
resp.eval 1 ⟨powerset, λ ⟨α, A⟩ ⟨β, B⟩ ⟨αβ, βα⟩, ⟨λ p, ⟨{b | ∃ a, p a ∧ equiv (A a) (B b)}, λ ⟨a, pa⟩, let ⟨b, ab⟩ := αβ a in ⟨⟨b, a, pa, ab⟩, ab⟩, λ ⟨b, a, pa, ab⟩, ⟨⟨a, pa⟩, ab⟩⟩, λ q, ⟨{a | ∃ b, q b ∧ equiv (A a) (B b)}, λ ⟨a, b, qb, ab⟩, ⟨⟨b, qb⟩, ab⟩, λ ⟨b, qb⟩, let ⟨a, ab⟩ := βα b in ⟨⟨a, b, ...
def
Set.powerset
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set", "equiv" ]
The powerset operation, the collection of subsets of a ZFC set
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_powerset {x y : Set.{u}} : y ∈ powerset x ↔ y ⊆ x
quotient.induction_on₂ x y ( λ ⟨α, A⟩ ⟨β, B⟩, show (⟨β, B⟩ : pSet.{u}) ∈ (pSet.powerset.{u} ⟨α, A⟩) ↔ _, by simp [mem_powerset, subset_iff])
theorem
Set.mem_powerset
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sUnion_lem {α β : Type u} (A : α → pSet) (B : β → pSet) (αβ : ∀ a, ∃ b, equiv (A a) (B b)) : ∀ a, ∃ b, (equiv ((sUnion ⟨α, A⟩).func a) ((sUnion ⟨β, B⟩).func b))
| ⟨a, c⟩ := let ⟨b, hb⟩ := αβ a in begin induction ea : A a with γ Γ, induction eb : B b with δ Δ, rw [ea, eb] at hb, cases hb with γδ δγ, exact let c : type (A a) := c, ⟨d, hd⟩ := γδ (by rwa ea at c) in have pSet.equiv ((A a).func c) ((B b).func (eq.rec d (eq.symm eb))), from match A ...
theorem
Set.sUnion_lem
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "equiv", "pSet", "pSet.equiv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sUnion : Set → Set
resp.eval 1 ⟨pSet.sUnion, λ ⟨α, A⟩ ⟨β, B⟩ ⟨αβ, βα⟩, ⟨sUnion_lem A B αβ, λ a, exists.elim (sUnion_lem B A (λ b, exists.elim (βα b) (λ c hc, ⟨c, pSet.equiv.symm hc⟩)) a) (λ b hb, ⟨b, pSet.equiv.symm hb⟩)⟩⟩
def
Set.sUnion
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set", "pSet.equiv.symm" ]
The union operator, the collection of elements of elements of a ZFC set
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sInter (x : Set) : Set
by { classical, exact dite x.nonempty (λ h, {y ∈ h.some | ∀ z ∈ x, y ∈ z}) (λ _, ∅) }
def
Set.sInter
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
The intersection operator, the collection of elements in all of the elements of a ZFC set. We special-case `⋂₀ ∅ = ∅`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_sUnion {x y : Set.{u}} : y ∈ ⋃₀ x ↔ ∃ z ∈ x, y ∈ z
quotient.induction_on₂ x y (λ x y, iff.trans mem_sUnion ⟨λ ⟨z, h⟩, ⟨⟦z⟧, h⟩, λ ⟨z, h⟩, quotient.induction_on z (λ z h, ⟨z, h⟩) h⟩)
theorem
Set.mem_sUnion
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_sInter {x y : Set} (h : x.nonempty) : y ∈ ⋂₀ x ↔ ∀ z ∈ x, y ∈ z
begin rw [sInter, dif_pos h], simp only [mem_to_set, mem_sep, and_iff_right_iff_imp], exact λ H, H _ h.some_mem end
theorem
Set.mem_sInter
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set", "and_iff_right_iff_imp" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sUnion_empty : ⋃₀ (∅ : Set) = ∅
by { ext, simp }
theorem
Set.sUnion_empty
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sInter_empty : ⋂₀ (∅ : Set) = ∅
dif_neg $ by simp
theorem
Set.sInter_empty
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_of_mem_sInter {x y z : Set} (hy : y ∈ ⋂₀ x) (hz : z ∈ x) : y ∈ z
begin rcases eq_empty_or_nonempty x with rfl | hx, { exact (not_mem_empty z hz).elim }, { exact (mem_sInter hx).1 hy z hz } end
theorem
Set.mem_of_mem_sInter
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_sUnion_of_mem {x y z : Set} (hy : y ∈ z) (hz : z ∈ x) : y ∈ ⋃₀ x
mem_sUnion.2 ⟨z, hz, hy⟩
theorem
Set.mem_sUnion_of_mem
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
not_mem_sInter_of_not_mem {x y z : Set} (hy : ¬ y ∈ z) (hz : z ∈ x) : ¬ y ∈ ⋂₀ x
λ hx, hy $ mem_of_mem_sInter hx hz
theorem
Set.not_mem_sInter_of_not_mem
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sUnion_singleton {x : Set.{u}} : ⋃₀ ({x} : Set) = x
ext $ λ y, by simp_rw [mem_sUnion, exists_prop, mem_singleton, exists_eq_left]
theorem
Set.sUnion_singleton
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set", "exists_eq_left", "exists_prop" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sInter_singleton {x : Set.{u}} : ⋂₀ ({x} : Set) = x
ext $ λ y, by simp_rw [mem_sInter (singleton_nonempty x), mem_singleton, forall_eq]
theorem
Set.sInter_singleton
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set", "forall_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_set_sUnion (x : Set.{u}) : (⋃₀ x).to_set = ⋃₀ (to_set '' x.to_set)
by { ext, simp }
theorem
Set.to_set_sUnion
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_set_sInter {x : Set.{u}} (h : x.nonempty) : (⋂₀ x).to_set = ⋂₀ (to_set '' x.to_set)
by { ext, simp [mem_sInter h] }
theorem
Set.to_set_sInter
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
singleton_injective : function.injective (@singleton Set Set _)
λ x y H, let this := congr_arg sUnion H in by rwa [sUnion_singleton, sUnion_singleton] at this
theorem
Set.singleton_injective
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
singleton_inj {x y : Set} : ({x} : Set) = {y} ↔ x = y
singleton_injective.eq_iff
theorem
Set.singleton_inj
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
union (x y : Set.{u}) : Set.{u}
⋃₀ {x, y}
def
Set.union
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
The binary union operation
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inter (x y : Set.{u}) : Set.{u}
{z ∈ x | z ∈ y}
def
Set.inter
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
The binary intersection operation
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diff (x y : Set.{u}) : Set.{u}
{z ∈ x | z ∉ y}
def
Set.diff
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
The set difference operation
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_set_union (x y : Set.{u}) : (x ∪ y).to_set = x.to_set ∪ y.to_set
by { unfold has_union.union, rw Set.union, simp }
theorem
Set.to_set_union
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set.union" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_set_inter (x y : Set.{u}) : (x ∩ y).to_set = x.to_set ∩ y.to_set
by { unfold has_inter.inter, rw Set.inter, ext, simp }
theorem
Set.to_set_inter
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set.inter" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_set_sdiff (x y : Set.{u}) : (x \ y).to_set = x.to_set \ y.to_set
by { change {z ∈ x | z ∉ y}.to_set = _, ext, simp }
theorem
Set.to_set_sdiff
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_union {x y z : Set.{u}} : z ∈ x ∪ y ↔ z ∈ x ∨ z ∈ y
by { rw ←mem_to_set, simp }
theorem
Set.mem_union
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_inter {x y z : Set.{u}} : z ∈ x ∩ y ↔ z ∈ x ∧ z ∈ y
@@mem_sep (λ z : Set.{u}, z ∈ y)
theorem
Set.mem_inter
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_diff {x y z : Set.{u}} : z ∈ x \ y ↔ z ∈ x ∧ z ∉ y
@@mem_sep (λ z : Set.{u}, z ∉ y)
theorem
Set.mem_diff
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sUnion_pair {x y : Set.{u}} : ⋃₀ ({x, y} : Set.{u}) = x ∪ y
begin ext, simp_rw [mem_union, mem_sUnion, mem_pair], split, { rintro ⟨w, (rfl | rfl), hw⟩, { exact or.inl hw }, { exact or.inr hw } }, { rintro (hz | hz), { exact ⟨x, or.inl rfl, hz⟩ }, { exact ⟨y, or.inr rfl, hz⟩ } } end
theorem
Set.sUnion_pair
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_wf : @well_founded Set (∈)
well_founded_lift₂_iff.mpr pSet.mem_wf
theorem
Set.mem_wf
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set", "pSet.mem_wf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
induction_on {p : Set → Prop} (x) (h : ∀ x, (∀ y ∈ x, p y) → p x) : p x
mem_wf.induction x h
theorem
Set.induction_on
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
Induction on the `∈` relation.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_asymm {x y : Set} : x ∈ y → y ∉ x
asymm
theorem
Set.mem_asymm
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_irrefl (x : Set) : x ∉ x
irrefl x
theorem
Set.mem_irrefl
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
regularity (x : Set.{u}) (h : x ≠ ∅) : ∃ y ∈ x, x ∩ y = ∅
classical.by_contradiction $ λ ne, h $ (eq_empty x).2 $ λ y, induction_on y $ λ z (IH : ∀ w : Set.{u}, w ∈ z → w ∉ x), show z ∉ x, from λ zx, ne ⟨z, zx, (eq_empty _).2 (λ w wxz, let ⟨wx, wz⟩ := mem_inter.1 wxz in IH w wz wx)⟩
theorem
Set.regularity
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
image (f : Set → Set) [H : definable 1 f] : Set → Set
let r := @definable.resp 1 f _ in resp.eval 1 ⟨image r.1, λ x y e, mem.ext $ λ z, iff.trans (mem_image r.2) $ iff.trans (by exact ⟨λ ⟨w, h1, h2⟩, ⟨w, (mem.congr_right e).1 h1, h2⟩, λ ⟨w, h1, h2⟩, ⟨w, (mem.congr_right e).2 h1, h2⟩⟩) $ iff.symm (mem_image r.2)⟩
def
Set.image
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
The image of a (definable) ZFC set function
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
image.mk : Π (f : Set.{u} → Set.{u}) [H : definable 1 f] (x) {y} (h : y ∈ x), f y ∈ @image f H x
| ._ ⟨F⟩ x y := quotient.induction_on₂ x y $ λ ⟨α, A⟩ y ⟨a, ya⟩, ⟨a, F.2 _ _ ya⟩
theorem
Set.image.mk
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_image : Π {f : Set.{u} → Set.{u}} [H : definable 1 f] {x y : Set.{u}}, y ∈ @image f H x ↔ ∃ z ∈ x, f z = y
| ._ ⟨F⟩ x y := quotient.induction_on₂ x y $ λ ⟨α, A⟩ y, ⟨λ ⟨a, ya⟩, ⟨⟦A a⟧, mem.mk A a, eq.symm $ quotient.sound ya⟩, λ ⟨z, hz, e⟩, e ▸ image.mk _ _ hz⟩
theorem
Set.mem_image
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_set_image (f : Set → Set) [H : definable 1 f] (x : Set) : (image f x).to_set = f '' x.to_set
by { ext, simp }
theorem
Set.to_set_image
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
range {α : Type u} (f : α → Set.{max u v}) : Set.{max u v}
⟦⟨ulift α, quotient.out ∘ f ∘ ulift.down⟩⟧
def
Set.range
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "quotient.out" ]
The range of an indexed family of sets. The universes allow for a more general index type without manual use of `ulift`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_range {α : Type u} {f : α → Set.{max u v}} {x : Set.{max u v}} : x ∈ range f ↔ x ∈ set.range f
quotient.induction_on x (λ y, begin split, { rintro ⟨z, hz⟩, exact ⟨z.down, quotient.eq_mk_iff_out.2 hz.symm⟩ }, { rintro ⟨z, hz⟩, use z, simpa [hz] using pSet.equiv.symm (quotient.mk_out y) } end)
theorem
Set.mem_range
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "pSet.equiv.symm", "quotient.mk_out", "set.range" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_set_range {α : Type u} (f : α → Set.{max u v}) : (range f).to_set = set.range f
by { ext, simp }
theorem
Set.to_set_range
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "set.range" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pair (x y : Set.{u}) : Set.{u}
{{x}, {x, y}}
def
Set.pair
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
Kuratowski ordered pair
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_set_pair (x y : Set.{u}) : (pair x y).to_set = {{x}, {x, y}}
by simp [pair]
theorem
Set.to_set_pair
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pair_sep (p : Set.{u} → Set.{u} → Prop) (x y : Set.{u}) : Set.{u}
{z ∈ powerset (powerset (x ∪ y)) | ∃ a ∈ x, ∃ b ∈ y, z = pair a b ∧ p a b}
def
Set.pair_sep
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
A subset of pairs `{(a, b) ∈ x × y | p a b}`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_pair_sep {p} {x y z : Set.{u}} : z ∈ pair_sep p x y ↔ ∃ a ∈ x, ∃ b ∈ y, z = pair a b ∧ p a b
begin refine mem_sep.trans ⟨and.right, λ e, ⟨_, e⟩⟩, rcases e with ⟨a, ax, b, bY, rfl, pab⟩, simp only [mem_powerset, subset_def, mem_union, pair, mem_pair], rintros u (rfl|rfl) v; simp only [mem_singleton, mem_pair], { rintro rfl, exact or.inl ax }, { rintro (rfl|rfl); [left, right]; assumption } end
theorem
Set.mem_pair_sep
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pair_injective : function.injective2 pair
λ x x' y y' H, begin have ae := ext_iff.1 H, simp only [pair, mem_pair] at ae, obtain rfl : x = x', { cases (ae {x}).1 (by simp) with h h, { exact singleton_injective h }, { have m : x' ∈ ({x} : Set), { simp [h] }, rw mem_singleton.mp m } }, have he : x = y → y = y', { rintro rfl, ca...
theorem
Set.pair_injective
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pair_inj {x y x' y' : Set} : pair x y = pair x' y' ↔ x = x' ∧ y = y'
pair_injective.eq_iff
theorem
Set.pair_inj
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod : Set.{u} → Set.{u} → Set.{u}
pair_sep (λ a b, true)
def
Set.prod
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
The cartesian product, `{(a, b) | a ∈ x, b ∈ y}`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_prod {x y z : Set.{u}} : z ∈ prod x y ↔ ∃ a ∈ x, ∃ b ∈ y, z = pair a b
by simp [prod]
theorem
Set.mem_prod
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pair_mem_prod {x y a b : Set.{u}} : pair a b ∈ prod x y ↔ a ∈ x ∧ b ∈ y
⟨λ h, let ⟨a', a'x, b', b'y, e⟩ := mem_prod.1 h in match a', b', pair_injective e, a'x, b'y with ._, ._, ⟨rfl, rfl⟩, ax, bY := ⟨ax, bY⟩ end, λ ⟨ax, bY⟩, mem_prod.2 ⟨a, ax, b, bY, rfl⟩⟩
theorem
Set.pair_mem_prod
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_func (x y f : Set.{u}) : Prop
f ⊆ prod x y ∧ ∀ z : Set.{u}, z ∈ x → ∃! w, pair z w ∈ f
def
Set.is_func
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
`is_func x y f` is the assertion that `f` is a subset of `x × y` which relates to each element of `x` a unique element of `y`, so that we can consider `f`as a ZFC function `x → y`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
funs (x y : Set.{u}) : Set.{u}
{f ∈ powerset (prod x y) | is_func x y f}
def
Set.funs
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
`funs x y` is `y ^ x`, the set of all set functions `x → y`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_funs {x y f : Set.{u}} : f ∈ funs x y ↔ is_func x y f
by simp [funs, is_func]
theorem
Set.mem_funs
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_definable_aux (f : Set → Set) [H : definable 1 f] : definable 1 (λ y, pair y (f y))
@classical.all_definable 1 _
instance
Set.map_definable_aux
set_theory.zfc
src/set_theory/zfc/basic.lean
[ "data.set.lattice", "logic.small.basic", "order.well_founded" ]
[ "Set", "classical.all_definable" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83