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nonempty [Mn : Nonempty M] (h : M ≅[L] N) : Nonempty N := h.nonempty_iff.1 Mn
theorem
ModelTheory
[ "Mathlib.Data.Finset.Basic", "Mathlib.ModelTheory.Syntax", "Mathlib.Data.List.ProdSigma" ]
Mathlib/ModelTheory/Semantics.lean
nonempty
null
infinite_iff (h : M ≅[L] N) : Infinite M ↔ Infinite N := (model_infiniteTheory_iff L).symm.trans (h.theory_model_iff.trans (model_infiniteTheory_iff L))
theorem
ModelTheory
[ "Mathlib.Data.Finset.Basic", "Mathlib.ModelTheory.Syntax", "Mathlib.Data.List.ProdSigma" ]
Mathlib/ModelTheory/Semantics.lean
infinite_iff
null
infinite [Mi : Infinite M] (h : M ≅[L] N) : Infinite N := h.infinite_iff.1 Mi
theorem
ModelTheory
[ "Mathlib.Data.Finset.Basic", "Mathlib.ModelTheory.Syntax", "Mathlib.Data.List.ProdSigma" ]
Mathlib/ModelTheory/Semantics.lean
infinite
null
@[simps] skolem₁ : Language := ⟨fun n => L.BoundedFormula Empty (n + 1), fun _ => Empty⟩ variable {L}
def
ModelTheory
[ "Mathlib.ModelTheory.ElementarySubstructures" ]
Mathlib/ModelTheory/Skolem.lean
skolem₁
A language consisting of Skolem functions for another language. Called `skolem₁` because it is the first step in building a Skolemization of a language.
card_functions_sum_skolem₁ : #(Σ n, (L.sum L.skolem₁).Functions n) = #(Σ n, L.BoundedFormula Empty (n + 1)) := by simp only [card_functions_sum, skolem₁_Functions, mk_sigma, sum_add_distrib'] conv_lhs => enter [2, 1, i]; rw [lift_id'.{u, v}] rw [add_comm, add_eq_max, max_eq_left] · refine sum_le_sum _ _ fun...
theorem
ModelTheory
[ "Mathlib.ModelTheory.ElementarySubstructures" ]
Mathlib/ModelTheory/Skolem.lean
card_functions_sum_skolem₁
null
card_functions_sum_skolem₁_le : #(Σ n, (L.sum L.skolem₁).Functions n) ≤ max ℵ₀ L.card := by rw [card_functions_sum_skolem₁] trans #(Σ n, L.BoundedFormula Empty n) · exact ⟨⟨Sigma.map Nat.succ fun _ => id, Nat.succ_injective.sigma_map fun _ => Function.injective_id⟩⟩ · refine _root_.trans Bounded...
theorem
ModelTheory
[ "Mathlib.ModelTheory.ElementarySubstructures" ]
Mathlib/ModelTheory/Skolem.lean
card_functions_sum_skolem₁_le
null
noncomputable skolem₁Structure : L.skolem₁.Structure M := ⟨fun {_} φ x => Classical.epsilon fun a => φ.Realize default (Fin.snoc x a : _ → M), fun {_} r => Empty.elim r⟩
instance
ModelTheory
[ "Mathlib.ModelTheory.ElementarySubstructures" ]
Mathlib/ModelTheory/Skolem.lean
skolem₁Structure
The structure assigning each function symbol of `L.skolem₁` to a skolem function generated with choice.
skolem₁_reduct_isElementary (S : (L.sum L.skolem₁).Substructure M) : (LHom.sumInl.substructureReduct S).IsElementary := by apply (LHom.sumInl.substructureReduct S).isElementary_of_exists intro n φ x a h let φ' : (L.sum L.skolem₁).Functions n := LHom.sumInr.onFunction φ use ⟨funMap φ' ((↑) ∘ x), ?_⟩ · exac...
theorem
ModelTheory
[ "Mathlib.ModelTheory.ElementarySubstructures" ]
Mathlib/ModelTheory/Skolem.lean
skolem₁_reduct_isElementary
null
noncomputable elementarySkolem₁Reduct (S : (L.sum L.skolem₁).Substructure M) : L.ElementarySubstructure M := ⟨LHom.sumInl.substructureReduct S, S.skolem₁_reduct_isElementary⟩
def
ModelTheory
[ "Mathlib.ModelTheory.ElementarySubstructures" ]
Mathlib/ModelTheory/Skolem.lean
elementarySkolem₁Reduct
Any `L.sum L.skolem₁`-substructure is an elementary `L`-substructure.
coeSort_elementarySkolem₁Reduct (S : (L.sum L.skolem₁).Substructure M) : (S.elementarySkolem₁Reduct : Type w) = S := rfl
theorem
ModelTheory
[ "Mathlib.ModelTheory.ElementarySubstructures" ]
Mathlib/ModelTheory/Skolem.lean
coeSort_elementarySkolem₁Reduct
null
Substructure.elementarySkolem₁Reduct.instSmall : Small.{max u v} (⊥ : (L.sum L.skolem₁).Substructure M).elementarySkolem₁Reduct := by rw [coeSort_elementarySkolem₁Reduct] infer_instance
instance
ModelTheory
[ "Mathlib.ModelTheory.ElementarySubstructures" ]
Mathlib/ModelTheory/Skolem.lean
Substructure.elementarySkolem₁Reduct.instSmall
null
exists_small_elementarySubstructure : ∃ S : L.ElementarySubstructure M, Small.{max u v} S := ⟨Substructure.elementarySkolem₁Reduct ⊥, inferInstance⟩ variable {M}
theorem
ModelTheory
[ "Mathlib.ModelTheory.ElementarySubstructures" ]
Mathlib/ModelTheory/Skolem.lean
exists_small_elementarySubstructure
null
exists_elementarySubstructure_card_eq (s : Set M) (κ : Cardinal.{w'}) (h1 : ℵ₀ ≤ κ) (h2 : Cardinal.lift.{w'} #s ≤ Cardinal.lift.{w} κ) (h3 : Cardinal.lift.{w'} L.card ≤ Cardinal.lift.{max u v} κ) (h4 : Cardinal.lift.{w} κ ≤ Cardinal.lift.{w'} #M) : ∃ S : L.ElementarySubstructure M, s ⊆ S ∧ Cardinal.lift...
theorem
ModelTheory
[ "Mathlib.ModelTheory.ElementarySubstructures" ]
Mathlib/ModelTheory/Skolem.lean
exists_elementarySubstructure_card_eq
The **Downward Löwenheim–Skolem theorem** : If `s` is a set in an `L`-structure `M` and `κ` an infinite cardinal such that `max (#s, L.card) ≤ κ` and `κ ≤ # M`, then `M` has an elementary substructure containing `s` of cardinality `κ`.
ClosedUnder : Prop := ∀ x : Fin n → M, (∀ i : Fin n, x i ∈ s) → funMap f x ∈ s variable (L) @[simp]
def
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
ClosedUnder
Indicates that a set in a given structure is a closed under a function symbol.
closedUnder_univ : ClosedUnder f (univ : Set M) := fun _ _ => mem_univ _ variable {L f s} {t : Set M}
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
closedUnder_univ
null
inter (hs : ClosedUnder f s) (ht : ClosedUnder f t) : ClosedUnder f (s ∩ t) := fun x h => mem_inter (hs x fun i => mem_of_mem_inter_left (h i)) (ht x fun i => mem_of_mem_inter_right (h i))
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
inter
null
inf (hs : ClosedUnder f s) (ht : ClosedUnder f t) : ClosedUnder f (s ⊓ t) := hs.inter ht variable {S : Set (Set M)}
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
inf
null
sInf (hS : ∀ s, s ∈ S → ClosedUnder f s) : ClosedUnder f (sInf S) := fun x h s hs => hS s hs x fun i => h i s hs
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
sInf
null
Substructure where /-- The underlying set of this substructure -/ carrier : Set M fun_mem : ∀ {n}, ∀ f : L.Functions n, ClosedUnder f carrier variable {L} {M}
structure
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
Substructure
A substructure of a structure `M` is a set closed under application of function symbols.
instSetLike : SetLike (L.Substructure M) M := ⟨Substructure.carrier, fun p q h => by cases p; cases q; congr⟩
instance
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
instSetLike
null
Simps.coe (S : L.Substructure M) : Set M := S initialize_simps_projections Substructure (carrier → coe, as_prefix coe) @[simp]
def
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
Simps.coe
See Note [custom simps projection]
mem_carrier {s : L.Substructure M} {x : M} : x ∈ s.carrier ↔ x ∈ s := Iff.rfl
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
mem_carrier
null
@[ext] ext {S T : L.Substructure M} (h : ∀ x, x ∈ S ↔ x ∈ T) : S = T := SetLike.ext h
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
ext
Two substructures are equal if they have the same elements.
protected copy (S : L.Substructure M) (s : Set M) (hs : s = S) : L.Substructure M where carrier := s fun_mem _ f := hs.symm ▸ S.fun_mem _ f
def
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
copy
Copy a substructure replacing `carrier` with a set that is equal to it.
Term.realize_mem {α : Type*} (t : L.Term α) (xs : α → M) (h : ∀ a, xs a ∈ S) : t.realize xs ∈ S := by induction t with | var a => exact h a | func f ts ih => exact Substructure.fun_mem _ _ _ ih
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
Term.realize_mem
null
@[simp] coe_copy {s : Set M} (hs : s = S) : (S.copy s hs : Set M) = s := rfl
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
coe_copy
null
copy_eq {s : Set M} (hs : s = S) : S.copy s hs = S := SetLike.coe_injective hs
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
copy_eq
null
constants_mem (c : L.Constants) : (c : M) ∈ S := mem_carrier.2 (S.fun_mem c _ finZeroElim)
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
constants_mem
null
instTop : Top (L.Substructure M) := ⟨{ carrier := Set.univ fun_mem := fun {_} _ _ _ => Set.mem_univ _ }⟩
instance
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
instTop
The substructure `M` of the structure `M`.
instInhabited : Inhabited (L.Substructure M) := ⟨⊤⟩ @[simp]
instance
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
instInhabited
null
mem_top (x : M) : x ∈ (⊤ : L.Substructure M) := Set.mem_univ x @[simp]
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
mem_top
null
coe_top : ((⊤ : L.Substructure M) : Set M) = Set.univ := rfl
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
coe_top
null
instInf : Min (L.Substructure M) := ⟨fun S₁ S₂ => { carrier := (S₁ : Set M) ∩ (S₂ : Set M) fun_mem := fun {_} f => (S₁.fun_mem f).inf (S₂.fun_mem f) }⟩ @[simp]
instance
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
instInf
The inf of two substructures is their intersection.
coe_inf (p p' : L.Substructure M) : ((p ⊓ p' : L.Substructure M) : Set M) = (p : Set M) ∩ (p' : Set M) := rfl @[simp]
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
coe_inf
null
mem_inf {p p' : L.Substructure M} {x : M} : x ∈ p ⊓ p' ↔ x ∈ p ∧ x ∈ p' := Iff.rfl
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
mem_inf
null
instInfSet : InfSet (L.Substructure M) := ⟨fun s => { carrier := ⋂ t ∈ s, (t : Set M) fun_mem := fun {n} f => ClosedUnder.sInf (by rintro _ ⟨t, rfl⟩ by_cases h : t ∈ s · simpa [h] using t.fun_mem f · simp [h]) }⟩ @[simp, norm_cast]
instance
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
instInfSet
null
coe_sInf (S : Set (L.Substructure M)) : ((sInf S : L.Substructure M) : Set M) = ⋂ s ∈ S, (s : Set M) := rfl
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
coe_sInf
null
mem_sInf {S : Set (L.Substructure M)} {x : M} : x ∈ sInf S ↔ ∀ p ∈ S, x ∈ p := Set.mem_iInter₂
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
mem_sInf
null
mem_iInf {ι : Sort*} {S : ι → L.Substructure M} {x : M} : (x ∈ ⨅ i, S i) ↔ ∀ i, x ∈ S i := by simp only [iInf, mem_sInf, Set.forall_mem_range] @[simp, norm_cast]
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
mem_iInf
null
coe_iInf {ι : Sort*} {S : ι → L.Substructure M} : ((⨅ i, S i : L.Substructure M) : Set M) = ⋂ i, (S i : Set M) := by simp only [iInf, coe_sInf, Set.biInter_range]
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
coe_iInf
null
instCompleteLattice : CompleteLattice (L.Substructure M) := { completeLatticeOfInf (L.Substructure M) fun _ => IsGLB.of_image (fun {S T : L.Substructure M} => show (S : Set M) ≤ T ↔ S ≤ T from SetLike.coe_subset_coe) isGLB_biInf with le := (· ≤ ·) lt := (· < ·) top := ⊤ le_top :=...
instance
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
instCompleteLattice
Substructures of a structure form a complete lattice.
closure : LowerAdjoint ((↑) : L.Substructure M → Set M) := ⟨fun s => sInf { S | s ⊆ S }, fun _ _ => ⟨Set.Subset.trans fun _x hx => mem_sInf.2 fun _S hS => hS hx, fun h => sInf_le h⟩⟩ variable {L} {s : Set M}
def
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
closure
The `L.Substructure` generated by a set.
mem_closure {x : M} : x ∈ closure L s ↔ ∀ S : L.Substructure M, s ⊆ S → x ∈ S := mem_sInf
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
mem_closure
null
@[simp] subset_closure : s ⊆ closure L s := (closure L).le_closure s
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
subset_closure
The substructure generated by a set includes the set.
notMem_of_notMem_closure {P : M} (hP : P ∉ closure L s) : P ∉ s := fun h => hP (subset_closure h) @[deprecated (since := "2025-05-23")] alias not_mem_of_not_mem_closure := notMem_of_notMem_closure @[simp]
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
notMem_of_notMem_closure
null
closed (S : L.Substructure M) : (closure L).closed (S : Set M) := congr rfl ((closure L).eq_of_le Set.Subset.rfl fun _x xS => mem_closure.2 fun _T hT => hT xS) open Set
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
closed
null
@[simp] closure_le : closure L s ≤ S ↔ s ⊆ S := (closure L).closure_le_closed_iff_le s S.closed
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
closure_le
A substructure `S` includes `closure L s` if and only if it includes `s`.
@[gcongr] closure_mono ⦃s t : Set M⦄ (h : s ⊆ t) : closure L s ≤ closure L t := (closure L).monotone h
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
closure_mono
Substructure closure of a set is monotone in its argument: if `s ⊆ t`, then `closure L s ≤ closure L t`.
closure_eq_of_le (h₁ : s ⊆ S) (h₂ : S ≤ closure L s) : closure L s = S := (closure L).eq_of_le h₁ h₂
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
closure_eq_of_le
null
coe_closure_eq_range_term_realize : (closure L s : Set M) = range (@Term.realize L _ _ _ ((↑) : s → M)) := by let S : L.Substructure M := ⟨range (Term.realize (L := L) ((↑) : s → M)), fun {n} f x hx => by simp only [mem_range] at * refine ⟨func f fun i => Classical.choose (hx i), ?_⟩ simp only [Term.r...
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
coe_closure_eq_range_term_realize
null
small_closure [Small.{u} s] : Small.{u} (closure L s) := by rw [← SetLike.coe_sort_coe, Substructure.coe_closure_eq_range_term_realize] exact small_range _
instance
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
small_closure
null
mem_closure_iff_exists_term {x : M} : x ∈ closure L s ↔ ∃ t : L.Term s, t.realize ((↑) : s → M) = x := by rw [← SetLike.mem_coe, coe_closure_eq_range_term_realize, mem_range]
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
mem_closure_iff_exists_term
null
lift_card_closure_le_card_term : Cardinal.lift.{max u w} #(closure L s) ≤ #(L.Term s) := by rw [← SetLike.coe_sort_coe, coe_closure_eq_range_term_realize] rw [← Cardinal.lift_id'.{w, max u w} #(L.Term s)] exact Cardinal.mk_range_le_lift
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
lift_card_closure_le_card_term
null
lift_card_closure_le : Cardinal.lift.{u, w} #(closure L s) ≤ max ℵ₀ (Cardinal.lift.{u, w} #s + Cardinal.lift.{w, u} #(Σ i, L.Functions i)) := by rw [← lift_umax] refine lift_card_closure_le_card_term.trans (Term.card_le.trans ?_) rw [mk_sum, lift_umax.{w, u}]
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
lift_card_closure_le
null
mem_closed_iff (s : Set M) : s ∈ (closure L).closed ↔ ∀ {n}, ∀ f : L.Functions n, ClosedUnder f s := by refine ⟨fun h n f => ?_, fun h => ?_⟩ · rw [← h] exact Substructure.fun_mem _ _ · have h' : closure L s = ⟨s, h⟩ := closure_eq_of_le (refl _) subset_closure exact congr_arg _ h' variable (L)
lemma
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
mem_closed_iff
null
mem_closed_of_isRelational [L.IsRelational] (s : Set M) : s ∈ (closure L).closed := (mem_closed_iff s).2 isEmptyElim @[simp]
lemma
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
mem_closed_of_isRelational
null
closure_eq_of_isRelational [L.IsRelational] (s : Set M) : closure L s = s := LowerAdjoint.closure_eq_self_of_mem_closed _ (mem_closed_of_isRelational L s) @[simp]
lemma
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
closure_eq_of_isRelational
null
mem_closure_iff_of_isRelational [L.IsRelational] (s : Set M) (m : M) : m ∈ closure L s ↔ m ∈ s := by rw [← SetLike.mem_coe, closure_eq_of_isRelational]
lemma
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
mem_closure_iff_of_isRelational
null
_root_.Set.Countable.substructure_closure [Countable (Σ l, L.Functions l)] (h : s.Countable) : Countable.{w + 1} (closure L s) := by haveI : Countable s := h.to_subtype rw [← mk_le_aleph0_iff, ← lift_le_aleph0] exact lift_card_closure_le_card_term.trans mk_le_aleph0 variable {L} (S)
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
_root_.Set.Countable.substructure_closure
null
@[elab_as_elim] closure_induction {p : M → Prop} {x} (h : x ∈ closure L s) (Hs : ∀ x ∈ s, p x) (Hfun : ∀ {n : ℕ} (f : L.Functions n), ClosedUnder f (setOf p)) : p x := (@closure_le L M _ ⟨setOf p, fun {_} => Hfun⟩ _).2 Hs h
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
closure_induction
An induction principle for closure membership. If `p` holds for all elements of `s`, and is preserved under function symbols, then `p` holds for all elements of the closure of `s`.
@[elab_as_elim] dense_induction {p : M → Prop} (x : M) {s : Set M} (hs : closure L s = ⊤) (Hs : ∀ x ∈ s, p x) (Hfun : ∀ {n : ℕ} (f : L.Functions n), ClosedUnder f (setOf p)) : p x := by have : ∀ x ∈ closure L s, p x := fun x hx => closure_induction hx Hs fun {n} => Hfun simpa [hs] using this x variable (L) (M)
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
dense_induction
If `s` is a dense set in a structure `M`, `Substructure.closure L s = ⊤`, then in order to prove that some predicate `p` holds for all `x : M` it suffices to verify `p x` for `x ∈ s`, and verify that `p` is preserved under function symbols.
protected gi : GaloisInsertion (@closure L M _) (↑) where choice s _ := closure L s gc := (closure L).gc le_l_u _ := subset_closure choice_eq _ _ := rfl variable {L} {M}
def
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
gi
`closure` forms a Galois insertion with the coercion to set.
@[simp] closure_eq : closure L (S : Set M) = S := (Substructure.gi L M).l_u_eq S @[simp]
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
closure_eq
Closure of a substructure `S` equals `S`.
closure_empty : closure L (∅ : Set M) = ⊥ := (Substructure.gi L M).gc.l_bot @[simp]
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
closure_empty
null
closure_univ : closure L (univ : Set M) = ⊤ := @coe_top L M _ ▸ closure_eq ⊤
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
closure_univ
null
closure_union (s t : Set M) : closure L (s ∪ t) = closure L s ⊔ closure L t := (Substructure.gi L M).gc.l_sup
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
closure_union
null
closure_iUnion {ι} (s : ι → Set M) : closure L (⋃ i, s i) = ⨆ i, closure L (s i) := (Substructure.gi L M).gc.l_iSup
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
closure_iUnion
null
closure_insert (s : Set M) (m : M) : closure L (insert m s) = closure L {m} ⊔ closure L s := closure_union {m} s
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
closure_insert
null
small_bot : Small.{u} (⊥ : L.Substructure M) := by rw [← closure_empty] haveI : Small.{u} (∅ : Set M) := small_subsingleton _ exact Substructure.small_closure
instance
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
small_bot
null
iSup_eq_closure {ι : Sort*} (S : ι → L.Substructure M) : ⨆ i, S i = closure L (⋃ i, (S i : Set M)) := by simp_rw [closure_iUnion, closure_eq]
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
iSup_eq_closure
null
mem_iSup_of_directed {ι : Type*} [hι : Nonempty ι] {S : ι → L.Substructure M} (hS : Directed (· ≤ ·) S) {x : M} : x ∈ ⨆ i, S i ↔ ∃ i, x ∈ S i := by refine ⟨?_, fun ⟨i, hi⟩ ↦ le_iSup S i hi⟩ suffices x ∈ closure L (⋃ i, (S i : Set M)) → ∃ i, x ∈ S i by simpa only [closure_iUnion, closure_eq (S _)] using ...
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
mem_iSup_of_directed
null
mem_sSup_of_directedOn {S : Set (L.Substructure M)} (Sne : S.Nonempty) (hS : DirectedOn (· ≤ ·) S) {x : M} : x ∈ sSup S ↔ ∃ s ∈ S, x ∈ s := by haveI : Nonempty S := Sne.to_subtype simp only [sSup_eq_iSup', mem_iSup_of_directed hS.directed_val, Subtype.exists, exists_prop] variable (L) (M)
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
mem_sSup_of_directedOn
null
@[simps] comap (φ : M →[L] N) (S : L.Substructure N) : L.Substructure M where carrier := φ ⁻¹' S fun_mem {n} f x hx := by rw [mem_preimage, φ.map_fun] exact S.fun_mem f (φ ∘ x) hx @[simp]
def
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
comap
The preimage of a substructure along a homomorphism is a substructure.
mem_comap {S : L.Substructure N} {f : M →[L] N} {x : M} : x ∈ S.comap f ↔ f x ∈ S := Iff.rfl
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
mem_comap
null
comap_comap (S : L.Substructure P) (g : N →[L] P) (f : M →[L] N) : (S.comap g).comap f = S.comap (g.comp f) := rfl @[simp]
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
comap_comap
null
comap_id (S : L.Substructure P) : S.comap (Hom.id _ _) = S := ext (by simp)
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
comap_id
null
@[simps] map (φ : M →[L] N) (S : L.Substructure M) : L.Substructure N where carrier := φ '' S fun_mem {n} f x hx := (mem_image _ _ _).1 ⟨funMap f fun i => Classical.choose (hx i), S.fun_mem f _ fun i => (Classical.choose_spec (hx i)).1, by simp only [Hom.map_fun, SetLike.mem_coe] e...
def
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
map
The image of a substructure along a homomorphism is a substructure.
mem_map {f : M →[L] N} {S : L.Substructure M} {y : N} : y ∈ S.map f ↔ ∃ x ∈ S, f x = y := Iff.rfl
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
mem_map
null
mem_map_of_mem (f : M →[L] N) {S : L.Substructure M} {x : M} (hx : x ∈ S) : f x ∈ S.map f := mem_image_of_mem f hx
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
mem_map_of_mem
null
apply_coe_mem_map (f : M →[L] N) (S : L.Substructure M) (x : S) : f x ∈ S.map f := mem_map_of_mem f x.prop
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
apply_coe_mem_map
null
map_map (g : N →[L] P) (f : M →[L] N) : (S.map f).map g = S.map (g.comp f) := SetLike.coe_injective <| image_image _ _ _
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
map_map
null
map_le_iff_le_comap {f : M →[L] N} {S : L.Substructure M} {T : L.Substructure N} : S.map f ≤ T ↔ S ≤ T.comap f := image_subset_iff
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
map_le_iff_le_comap
null
gc_map_comap (f : M →[L] N) : GaloisConnection (map f) (comap f) := fun _ _ => map_le_iff_le_comap
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
gc_map_comap
null
map_le_of_le_comap {T : L.Substructure N} {f : M →[L] N} : S ≤ T.comap f → S.map f ≤ T := (gc_map_comap f).l_le
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
map_le_of_le_comap
null
le_comap_of_map_le {T : L.Substructure N} {f : M →[L] N} : S.map f ≤ T → S ≤ T.comap f := (gc_map_comap f).le_u
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
le_comap_of_map_le
null
le_comap_map {f : M →[L] N} : S ≤ (S.map f).comap f := (gc_map_comap f).le_u_l _
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
le_comap_map
null
map_comap_le {S : L.Substructure N} {f : M →[L] N} : (S.comap f).map f ≤ S := (gc_map_comap f).l_u_le _
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
map_comap_le
null
monotone_map {f : M →[L] N} : Monotone (map f) := (gc_map_comap f).monotone_l
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
monotone_map
null
monotone_comap {f : M →[L] N} : Monotone (comap f) := (gc_map_comap f).monotone_u @[simp]
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
monotone_comap
null
map_comap_map {f : M →[L] N} : ((S.map f).comap f).map f = S.map f := (gc_map_comap f).l_u_l_eq_l _ @[simp]
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
map_comap_map
null
comap_map_comap {S : L.Substructure N} {f : M →[L] N} : ((S.comap f).map f).comap f = S.comap f := (gc_map_comap f).u_l_u_eq_u _
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
comap_map_comap
null
map_sup (S T : L.Substructure M) (f : M →[L] N) : (S ⊔ T).map f = S.map f ⊔ T.map f := (gc_map_comap f).l_sup
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
map_sup
null
map_iSup {ι : Sort*} (f : M →[L] N) (s : ι → L.Substructure M) : (⨆ i, s i).map f = ⨆ i, (s i).map f := (gc_map_comap f).l_iSup
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
map_iSup
null
comap_inf (S T : L.Substructure N) (f : M →[L] N) : (S ⊓ T).comap f = S.comap f ⊓ T.comap f := (gc_map_comap f).u_inf
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
comap_inf
null
comap_iInf {ι : Sort*} (f : M →[L] N) (s : ι → L.Substructure N) : (⨅ i, s i).comap f = ⨅ i, (s i).comap f := (gc_map_comap f).u_iInf @[simp]
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
comap_iInf
null
map_bot (f : M →[L] N) : (⊥ : L.Substructure M).map f = ⊥ := (gc_map_comap f).l_bot @[simp]
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
map_bot
null
comap_top (f : M →[L] N) : (⊤ : L.Substructure N).comap f = ⊤ := (gc_map_comap f).u_top @[simp]
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
comap_top
null
map_id (S : L.Substructure M) : S.map (Hom.id L M) = S := SetLike.coe_injective <| Set.image_id _
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
map_id
null
map_closure (f : M →[L] N) (s : Set M) : (closure L s).map f = closure L (f '' s) := Eq.symm <| closure_eq_of_le (Set.image_mono subset_closure) <| map_le_iff_le_comap.2 <| closure_le.2 fun x hx => subset_closure ⟨x, hx, rfl⟩ @[simp]
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
map_closure
null
closure_image (f : M →[L] N) : closure L (f '' s) = map f (closure L s) := (map_closure f s).symm
theorem
ModelTheory
[ "Mathlib.Data.Fintype.Order", "Mathlib.Order.Closure", "Mathlib.ModelTheory.Semantics", "Mathlib.ModelTheory.Encoding" ]
Mathlib/ModelTheory/Substructures.lean
closure_image
null