--- /dev/null
+(**************************************************************************)
+(* ___ *)
+(* ||M|| *)
+(* ||A|| A project by Andrea Asperti *)
+(* ||T|| *)
+(* ||I|| Developers: *)
+(* ||T|| The HELM team. *)
+(* ||A|| http://helm.cs.unibo.it *)
+(* \ / *)
+(* \ / This file is distributed under the terms of the *)
+(* v GNU General Public License Version 2 *)
+(* *)
+(**************************************************************************)
+
+include "logic/cprop_connectives.ma".
+
+definition Type0 := Type.
+definition Type1 := Type.
+definition Type2 := Type.
+definition Type3 := Type.
+definition Type0_lt_Type1 := (Type0 : Type1).
+definition Type1_lt_Type2 := (Type1 : Type2).
+definition Type2_lt_Type3 := (Type2 : Type3).
+
+definition Type_OF_Type0: Type0 → Type := λx.x.
+definition Type_OF_Type1: Type1 → Type := λx.x.
+definition Type_OF_Type2: Type2 → Type := λx.x.
+definition Type_OF_Type3: Type3 → Type := λx.x.
+coercion Type_OF_Type0.
+coercion Type_OF_Type1.
+coercion Type_OF_Type2.
+coercion Type_OF_Type3.
+
+definition CProp0 := CProp.
+definition CProp1 := CProp.
+definition CProp2 := CProp.
+definition CProp0_lt_CProp1 := (CProp0 : CProp1).
+definition CProp1_lt_CProp2 := (CProp1 : CProp2).
+
+definition CProp_OF_CProp0: CProp0 → CProp := λx.x.
+definition CProp_OF_CProp1: CProp1 → CProp := λx.x.
+definition CProp_OF_CProp2: CProp2 → CProp := λx.x.
+
+record equivalence_relation (A:Type0) : Type1 ≝
+ { eq_rel:2> A → A → CProp0;
+ refl: reflexive ? eq_rel;
+ sym: symmetric ? eq_rel;
+ trans: transitive ? eq_rel
+ }.
+
+record setoid : Type1 ≝
+ { carr:> Type0;
+ eq: equivalence_relation carr
+ }.
+
+definition reflexive1 ≝ λA:Type1.λR:A→A→CProp1.∀x:A.R x x.
+definition symmetric1 ≝ λC:Type1.λlt:C→C→CProp1. ∀x,y:C.lt x y → lt y x.
+definition transitive1 ≝ λA:Type1.λR:A→A→CProp1.∀x,y,z:A.R x y → R y z → R x z.
+
+record equivalence_relation1 (A:Type1) : Type1 ≝
+ { eq_rel1:2> A → A → CProp1;
+ refl1: reflexive1 ? eq_rel1;
+ sym1: symmetric1 ? eq_rel1;
+ trans1: transitive1 ? eq_rel1
+ }.
+
+record setoid1: Type2 ≝
+ { carr1:> Type1;
+ eq1: equivalence_relation1 carr1
+ }.
+
+definition setoid1_of_setoid: setoid → setoid1.
+ intro;
+ constructor 1;
+ [ apply (carr s)
+ | constructor 1;
+ [ apply (eq_rel s);
+ apply (eq s)
+ | apply (refl s)
+ | apply (sym s)
+ | apply (trans s)]]
+qed.
+
+(* questa coercion e' necessaria per problemi di unificazione *)
+coercion setoid1_of_setoid.
+
+definition reflexive2 ≝ λA:Type2.λR:A→A→CProp2.∀x:A.R x x.
+definition symmetric2 ≝ λC:Type2.λlt:C→C→CProp2. ∀x,y:C.lt x y → lt y x.
+definition transitive2 ≝ λA:Type2.λR:A→A→CProp2.∀x,y,z:A.R x y → R y z → R x z.
+
+record equivalence_relation2 (A:Type2) : Type2 ≝
+ { eq_rel2:2> A → A → CProp2;
+ refl2: reflexive2 ? eq_rel2;
+ sym2: symmetric2 ? eq_rel2;
+ trans2: transitive2 ? eq_rel2
+ }.
+
+record setoid2: Type3 ≝
+ { carr2:> Type2;
+ eq2: equivalence_relation2 carr2
+ }.
+
+(*
+definition Leibniz: Type → setoid.
+ intro;
+ constructor 1;
+ [ apply T
+ | constructor 1;
+ [ apply (λx,y:T.cic:/matita/logic/equality/eq.ind#xpointer(1/1) ? x y)
+ | alias id "refl_eq" = "cic:/matita/logic/equality/eq.ind#xpointer(1/1/1)".
+ apply refl_eq
+ | alias id "sym_eq" = "cic:/matita/logic/equality/sym_eq.con".
+ apply sym_eq
+ | alias id "trans_eq" = "cic:/matita/logic/equality/trans_eq.con".
+ apply trans_eq ]]
+qed.
+
+coercion Leibniz.
+*)
+
+interpretation "setoid2 eq" 'eq x y = (eq_rel2 _ (eq2 _) x y).
+interpretation "setoid1 eq" 'eq x y = (eq_rel1 _ (eq1 _) x y).
+interpretation "setoid eq" 'eq x y = (eq_rel _ (eq _) x y).
+interpretation "setoid2 symmetry" 'invert r = (sym2 ____ r).
+interpretation "setoid1 symmetry" 'invert r = (sym1 ____ r).
+interpretation "setoid symmetry" 'invert r = (sym ____ r).
+notation ".= r" with precedence 50 for @{'trans $r}.
+interpretation "trans2" 'trans r = (trans2 _____ r).
+interpretation "trans1" 'trans r = (trans1 _____ r).
+interpretation "trans" 'trans r = (trans _____ r).
+
+record unary_morphism (A,B: setoid) : Type0 ≝
+ { fun1:1> A → B;
+ prop1: ∀a,a'. eq ? a a' → eq ? (fun1 a) (fun1 a')
+ }.
+
+record unary_morphism1 (A,B: setoid1) : Type1 ≝
+ { fun11:1> A → B;
+ prop11: ∀a,a'. eq1 ? a a' → eq1 ? (fun11 a) (fun11 a')
+ }.
+
+record unary_morphism2 (A,B: setoid2) : Type2 ≝
+ { fun12:1> A → B;
+ prop12: ∀a,a'. eq2 ? a a' → eq2 ? (fun12 a) (fun12 a')
+ }.
+
+record binary_morphism (A,B,C:setoid) : Type0 ≝
+ { fun2:2> A → B → C;
+ prop2: ∀a,a',b,b'. eq ? a a' → eq ? b b' → eq ? (fun2 a b) (fun2 a' b')
+ }.
+
+record binary_morphism1 (A,B,C:setoid1) : Type1 ≝
+ { fun21:2> A → B → C;
+ prop21: ∀a,a',b,b'. eq1 ? a a' → eq1 ? b b' → eq1 ? (fun21 a b) (fun21 a' b')
+ }.
+
+record binary_morphism2 (A,B,C:setoid2) : Type2 ≝
+ { fun22:2> A → B → C;
+ prop22: ∀a,a',b,b'. eq2 ? a a' → eq2 ? b b' → eq2 ? (fun22 a b) (fun22 a' b')
+ }.
+
+notation "† c" with precedence 90 for @{'prop1 $c }.
+notation "l ‡ r" with precedence 90 for @{'prop2 $l $r }.
+notation "#" with precedence 90 for @{'refl}.
+interpretation "prop1" 'prop1 c = (prop1 _____ c).
+interpretation "prop11" 'prop1 c = (prop11 _____ c).
+interpretation "prop12" 'prop1 c = (prop12 _____ c).
+interpretation "prop2" 'prop2 l r = (prop2 ________ l r).
+interpretation "prop21" 'prop2 l r = (prop21 ________ l r).
+interpretation "refl" 'refl = (refl ___).
+interpretation "refl1" 'refl = (refl1 ___).
+interpretation "refl2" 'refl = (refl2 ___).
+
+definition CPROP: setoid1.
+ constructor 1;
+ [ apply CProp0
+ | constructor 1;
+ [ apply Iff
+ | intros 1; split; intro; assumption
+ | intros 3; cases H; split; assumption
+ | intros 5; cases H; cases H1; split; intro;
+ [ apply (H4 (H2 x1)) | apply (H3 (H5 z1))]]]
+qed.
+
+definition if': ∀A,B:CPROP. A = B → A → B.
+ intros; apply (if ?? e); assumption.
+qed.
+
+notation ". r" with precedence 50 for @{'if $r}.
+interpretation "if" 'if r = (if' __ r).
+
+definition and_morphism: binary_morphism1 CPROP CPROP CPROP.
+ constructor 1;
+ [ apply And
+ | intros; split; intro; cases H; split;
+ [ apply (if ?? e a1)
+ | apply (if ?? e1 b1)
+ | apply (fi ?? e a1)
+ | apply (fi ?? e1 b1)]]
+qed.
+
+interpretation "and_morphism" 'and a b = (fun21 ___ and_morphism a b).
+
+definition or_morphism: binary_morphism1 CPROP CPROP CPROP.
+ constructor 1;
+ [ apply Or
+ | intros; split; intro; cases H; [1,3:left |2,4: right]
+ [ apply (if ?? e a1)
+ | apply (fi ?? e a1)
+ | apply (if ?? e1 b1)
+ | apply (fi ?? e1 b1)]]
+qed.
+
+interpretation "or_morphism" 'or a b = (fun21 ___ or_morphism a b).
+
+definition if_morphism: binary_morphism1 CPROP CPROP CPROP.
+ constructor 1;
+ [ apply (λA,B. A → B)
+ | intros; split; intros;
+ [ apply (if ?? e1); apply H; apply (fi ?? e); assumption
+ | apply (fi ?? e1); apply H; apply (if ?? e); assumption]]
+qed.
+
+(*
+definition eq_morphism: ∀S:setoid. binary_morphism S S CPROP.
+ intro;
+ constructor 1;
+ [ apply (eq_rel ? (eq S))
+ | intros; split; intro;
+ [ apply (.= H \sup -1);
+ apply (.= H2);
+ assumption
+ | apply (.= H);
+ apply (.= H2);
+ apply (H1 \sup -1)]]
+qed.
+*)
+
+record category : Type1 ≝
+ { objs:> Type0;
+ arrows: objs → objs → setoid;
+ id: ∀o:objs. arrows o o;
+ comp: ∀o1,o2,o3. binary_morphism1 (arrows o1 o2) (arrows o2 o3) (arrows o1 o3);
+ comp_assoc: ∀o1,o2,o3,o4. ∀a12,a23,a34.
+ comp o1 o3 o4 (comp o1 o2 o3 a12 a23) a34 = comp o1 o2 o4 a12 (comp o2 o3 o4 a23 a34);
+ id_neutral_left: ∀o1,o2. ∀a: arrows o1 o2. comp ??? (id o1) a = a;
+ id_neutral_right: ∀o1,o2. ∀a: arrows o1 o2. comp ??? a (id o2) = a
+ }.
+
+record category1 : Type2 ≝
+ { objs1:> Type1;
+ arrows1: objs1 → objs1 → setoid1;
+ id1: ∀o:objs1. arrows1 o o;
+ comp1: ∀o1,o2,o3. binary_morphism1 (arrows1 o1 o2) (arrows1 o2 o3) (arrows1 o1 o3);
+ comp_assoc1: ∀o1,o2,o3,o4. ∀a12,a23,a34.
+ comp1 o1 o3 o4 (comp1 o1 o2 o3 a12 a23) a34 = comp1 o1 o2 o4 a12 (comp1 o2 o3 o4 a23 a34);
+ id_neutral_right1: ∀o1,o2. ∀a: arrows1 o1 o2. comp1 ??? (id1 o1) a = a;
+ id_neutral_left1: ∀o1,o2. ∀a: arrows1 o1 o2. comp1 ??? a (id1 o2) = a
+ }.
+
+record category2 : Type3 ≝
+ { objs2:> Type2;
+ arrows2: objs2 → objs2 → setoid2;
+ id2: ∀o:objs2. arrows2 o o;
+ comp2: ∀o1,o2,o3. binary_morphism2 (arrows2 o1 o2) (arrows2 o2 o3) (arrows2 o1 o3);
+ comp_assoc2: ∀o1,o2,o3,o4. ∀a12,a23,a34.
+ comp2 o1 o3 o4 (comp2 o1 o2 o3 a12 a23) a34 = comp2 o1 o2 o4 a12 (comp2 o2 o3 o4 a23 a34);
+ id_neutral_right2: ∀o1,o2. ∀a: arrows2 o1 o2. comp2 ??? (id2 o1) a = a;
+ id_neutral_left2: ∀o1,o2. ∀a: arrows2 o1 o2. comp2 ??? a (id2 o2) = a
+ }.
+
+notation "'ASSOC'" with precedence 90 for @{'assoc}.
+notation "'ASSOC1'" with precedence 90 for @{'assoc1}.
+notation "'ASSOC2'" with precedence 90 for @{'assoc2}.
+
+interpretation "category1 composition" 'compose x y = (fun22 ___ (comp2 ____) y x).
+interpretation "category1 assoc" 'assoc1 = (comp_assoc2 ________).
+interpretation "category1 composition" 'compose x y = (fun21 ___ (comp1 ____) y x).
+interpretation "category1 assoc" 'assoc1 = (comp_assoc1 ________).
+interpretation "category composition" 'compose x y = (fun2 ___ (comp ____) y x).
+interpretation "category assoc" 'assoc = (comp_assoc ________).
+
+(* bug grande come una casa?
+ Ma come fa a passare la quantificazione larga??? *)
+definition unary_morphism_setoid: setoid → setoid → setoid.
+ intros;
+ constructor 1;
+ [ apply (unary_morphism s s1);
+ | constructor 1;
+ [ intros (f g); apply (∀a:s. f a = g a);
+ | intros 1; simplify; intros; apply refl;
+ | simplify; intros; apply sym; apply H;
+ | simplify; intros; apply trans; [2: apply H; | skip | apply H1]]]
+qed.
+
+definition SET: category1.
+ constructor 1;
+ [ apply setoid;
+ | apply rule (λS,T:setoid.unary_morphism_setoid S T);
+ | intros; constructor 1; [ apply (λx:carr o.x); | intros; assumption ]
+ | intros; constructor 1; [ intros; constructor 1; [ apply (λx. t1 (t x)); | intros;
+ apply († (†e));]
+ | intros; whd; intros; simplify; whd in H1; whd in H;
+ apply trans; [ apply (b (a' a1)); | lapply (prop1 ?? b (a a1) (a' a1));
+ [ apply Hletin | apply (e a1); ] | apply e1; ]]
+ | intros; whd; intros; simplify; apply refl;
+ | intros; simplify; whd; intros; simplify; apply refl;
+ | intros; simplify; whd; intros; simplify; apply refl;
+ ]
+qed.
+
+definition setoid_of_SET: objs1 SET → setoid.
+ intros; apply o; qed.
+coercion setoid_of_SET.
+
+definition setoid1_of_SET: SET → setoid1.
+ intro; whd in t; apply setoid1_of_setoid; apply t.
+qed.
+coercion setoid1_of_SET.
+
+definition eq': ∀w:SET.equivalence_relation ? := λw.eq w.
+
+definition prop1_SET :
+ ∀A,B:SET.∀w:arrows1 SET A B.∀a,b:Type_OF_objs1 A.eq' ? a b→eq' ? (w a) (w b).
+intros; apply (prop1 A B w a b e);
+qed.
+
+
+interpretation "SET dagger" 'prop1 h = (prop1_SET _ _ _ _ _ h).
+notation "hbox(a break ⇒ b)" right associative with precedence 20 for @{ 'Imply $a $b }.
+interpretation "unary morphism" 'Imply a b = (arrows1 SET a b).
+interpretation "SET eq" 'eq x y = (eq_rel _ (eq' _) x y).
+
+definition unary_morphism1_setoid1: setoid1 → setoid1 → setoid2.
+ intros;
+ constructor 1;
+ [ apply (unary_morphism1 s s1);
+ | constructor 1;
+ [ intros (f g); apply (∀a: carr1 s. f a = g a);
+ | intros 1; simplify; intros; apply refl1;
+ | simplify; intros; apply sym1; apply H;
+ | simplify; intros; apply trans1; [2: apply H; | skip | apply H1]]]
+qed.
+
+definition SET1: category2.
+ constructor 1;
+ [ apply setoid1;
+ | apply rule (λS,T.unary_morphism1_setoid1 S T);
+ | intros; constructor 1; [ apply (λx.x); | intros; assumption ]
+ | intros; constructor 1; [ intros; constructor 1; [ apply (λx. t1 (t x)); | intros;
+ apply († (†e));]
+ | intros; whd; intros; simplify; whd in H1; whd in H;
+ apply trans1; [ apply (b (a' a1)); | lapply (prop11 ?? b (a a1) (a' a1));
+ [ apply Hletin | apply (e a1); ] | apply e1; ]]
+ | intros; whd; intros; simplify; apply refl1;
+ | intros; simplify; whd; intros; simplify; apply refl1;
+ | intros; simplify; whd; intros; simplify; apply refl1;
+ ]
+qed.
+
+definition setoid1_OF_SET1: objs2 SET1 → setoid1.
+ intros; apply o; qed.
+
+coercion setoid1_OF_SET1.
+
+definition eq'': ∀w:SET1.equivalence_relation1 ? := λw.eq1 w.
+
+definition prop11_SET1 :
+ ∀A,B:SET1.∀w:arrows2 SET1 A B.∀a,b:Type_OF_objs2 A.eq'' ? a b→eq'' ? (w a) (w b).
+intros; apply (prop11 A B w a b e);
+qed.
+
+interpretation "SET dagger" 'prop1 h = (prop11_SET1 _ _ _ _ _ h).
+notation "hbox(a break ⇒ b)" right associative with precedence 20 for @{ 'Imply $a $b }.
+interpretation "unary morphism1" 'Imply a b = (arrows2 SET1 a b).
+interpretation "SET1 eq" 'eq x y = (eq_rel1 _ (eq'' _) x y).
\ No newline at end of file
(* *)
(**************************************************************************)
-include "datatypes/categories.ma".
+include "categories.ma".
include "logic/cprop_connectives.ma".
-inductive bool : Type := true : bool | false : bool.
+inductive bool : Type0 := true : bool | false : bool.
lemma BOOL : objs1 SET.
constructor 1; [apply bool] constructor 1;
interpretation "unary morphism comprehension with no proof" 'comprehension T P =
(mk_unary_morphism T _ P _).
+interpretation "unary morphism1 comprehension with no proof" 'comprehension T P =
+ (mk_unary_morphism1 T _ P _).
notation > "hvbox({ ident i ∈ s | term 19 p | by })" with precedence 90
for @{ 'comprehension_by $s (λ${ident i}. $p) $by}.
interpretation "unary morphism comprehension with proof" 'comprehension_by s \eta.f p =
(mk_unary_morphism s _ f p).
+interpretation "unary morphism1 comprehension with proof" 'comprehension_by s \eta.f p =
+ (mk_unary_morphism1 s _ f p).
+
+definition Type_of_SET: SET → Type0 := λS.carr S.
+coercion Type_of_SET.
(* per il set-indexing vedere capitolo BPTools (foundational tools), Sect. 0.3.4 complete
lattices, Definizione 0.9 *)
(* USARE L'ESISTENZIALE DEBOLE *)
(* Far salire SET usando setoidi1 *)
-record OAlgebra : Type := {
+alias symbol "comprehension_by" = "unary morphism comprehension with proof".
+record OAlgebra : Type1 := {
oa_P :> SET;
- oa_leq : binary_morphism1 oa_P oa_P CPROP; (* CPROP is setoid1, CPROP importante che sia small *)
- oa_overlap: binary_morphism1 oa_P oa_P CPROP;
- oa_meet: ∀I:SET.unary_morphism (arrows1 SET I oa_P) oa_P;
- oa_join: ∀I:SET.unary_morphism (arrows1 SET I oa_P) oa_P;
+ oa_leq : binary_morphism1 (setoid1_of_setoid oa_P) (setoid1_of_setoid oa_P) CPROP; (* CPROP is setoid1, CPROP importante che sia small *)
+ oa_overlap: binary_morphism1 (setoid1_of_setoid oa_P) (setoid1_of_setoid oa_P) CPROP;
+ oa_meet: ∀I:SET.unary_morphism1 (arrows1 SET I oa_P) (setoid1_of_setoid oa_P);
+ oa_join: ∀I:SET.unary_morphism1 (arrows1 SET I oa_P) (setoid1_of_setoid oa_P);
oa_one: oa_P;
oa_zero: oa_P;
oa_leq_refl: ∀a:oa_P. oa_leq a a;
oa_one_top: ∀p:oa_P.oa_leq p oa_one;
(* preservers!! (typo) *)
oa_overlap_preservers_meet_:
- ∀p,q.oa_overlap p q → oa_overlap p
+ ∀p,q:oa_P.oa_overlap p q → oa_overlap p
(oa_meet ? { x ∈ BOOL | match x with [ true ⇒ p | false ⇒ q ] | IF_THEN_ELSE_p oa_P p q });
(* ⇔ deve essere =, l'esiste debole *)
oa_join_split:
for @{ 'oa_meet (mk_unary_morphism BOOL ? (λx__:bool.match x__ with [ true ⇒ $a | false ⇒ $b ]) (IF_THEN_ELSE_p ? $a $b)) }.
*)
interpretation "o-algebra meet" 'oa_meet f =
- (fun_1 __ (oa_meet __) f).
+ (fun11 __ (oa_meet __) f).
interpretation "o-algebra meet with explicit function" 'oa_meet_mk f =
- (fun_1 __ (oa_meet __) (mk_unary_morphism _ _ f _)).
+ (fun11 __ (oa_meet __) (mk_unary_morphism _ _ f _)).
definition binary_meet : ∀O:OAlgebra. binary_morphism1 O O O.
intros; split;
--- /dev/null
+(**************************************************************************)
+(* ___ *)
+(* ||M|| *)
+(* ||A|| A project by Andrea Asperti *)
+(* ||T|| *)
+(* ||I|| Developers: *)
+(* ||T|| The HELM team. *)
+(* ||A|| http://helm.cs.unibo.it *)
+(* \ / *)
+(* \ / This file is distributed under the terms of the *)
+(* v GNU General Public License Version 2 *)
+(* *)
+(**************************************************************************)
+
+include "logic/cprop_connectives.ma".
+include "categories.ma".
+
+record powerset_carrier (A: SET) : Type1 ≝ { mem_operator: unary_morphism1 A CPROP }.
+
+definition subseteq_operator: ∀A: SET. powerset_carrier A → powerset_carrier A → CProp2 ≝
+ λA:SET.λU,V.∀a:A. mem_operator ? U a → mem_operator ? V a.
+
+theorem transitive_subseteq_operator: ∀A. transitive2 ? (subseteq_operator A).
+ intros 6; intros 2;
+ apply s1; apply s;
+ assumption.
+qed.
+
+definition powerset_setoid1: SET → SET1.
+ intros (T);
+ constructor 1;
+ [ apply (powerset_carrier T)
+ | constructor 1;
+ [ apply (λU,V. subseteq_operator ? U V ∧ subseteq_operator ? V U)
+ | simplify; intros; split; intros 2; assumption
+ | simplify; intros (x y H); cases H; split; assumption
+ | simplify; intros (x y z H H1); cases H; cases H1; split;
+ apply transitive_subseteq_operator; [1,4: apply y ]
+ assumption ]]
+qed.
+
+interpretation "powerset" 'powerset A = (powerset_setoid1 A).
+
+interpretation "subset construction" 'subset \eta.x =
+ (mk_powerset_carrier _ (mk_unary_morphism1 _ CPROP x _)).
+
+definition mem: ∀A. binary_morphism1 A (Ω \sup A) CPROP.
+ intros;
+ constructor 1;
+ [ apply (λx,S. mem_operator ? S x)
+ | intros 5;
+ cases b; clear b; cases b'; clear b'; simplify; intros;
+ apply (trans1 ????? (prop11 ?? u ?? e));
+ cases e1; whd in s s1;
+ split; intro;
+ [ apply s; assumption
+ | apply s1; assumption]]
+qed.
+
+interpretation "mem" 'mem a S = (fun21 ___ (mem _) a S).
+
+definition subseteq: ∀A. binary_morphism1 (Ω \sup A) (Ω \sup A) CPROP.
+ intros;
+ constructor 1;
+ [ apply (λU,V. subseteq_operator ? U V)
+ | intros;
+ cases e; cases e1;
+ split; intros 1;
+ [ apply (transitive_subseteq_operator ????? s2);
+ apply (transitive_subseteq_operator ???? s1 s4)
+ | apply (transitive_subseteq_operator ????? s3);
+ apply (transitive_subseteq_operator ???? s s4) ]]
+qed.
+
+interpretation "subseteq" 'subseteq U V = (fun21 ___ (subseteq _) U V).
+
+theorem subseteq_refl: ∀A.∀S:Ω \sup A.S ⊆ S.
+ intros 4; assumption.
+qed.
+
+theorem subseteq_trans: ∀A.∀S1,S2,S3: Ω \sup A. S1 ⊆ S2 → S2 ⊆ S3 → S1 ⊆ S3.
+ intros; apply transitive_subseteq_operator; [apply S2] assumption.
+qed.
+
+definition overlaps: ∀A. binary_morphism1 (Ω \sup A) (Ω \sup A) CPROP.
+ intros;
+ constructor 1;
+ [ apply (λA.λU,V:Ω \sup A.exT2 ? (λx:A.x ∈ U) (λx:A.x ∈ V))
+ | intros;
+ constructor 1; intro; cases H; exists; [1,4: apply w]
+ [ apply (. #‡e); assumption
+ | apply (. #‡e1); assumption
+ | apply (. #‡(e \sup -1)); assumption;
+ | apply (. #‡(e1 \sup -1)); assumption]]
+qed.
+
+interpretation "overlaps" 'overlaps U V = (fun21 ___ (overlaps _) U V).
+
+definition intersects:
+ ∀A. binary_morphism1 (Ω \sup A) (Ω \sup A) (Ω \sup A).
+ intros;
+ constructor 1;
+ [ apply rule (λU,V. {x | x ∈ U ∧ x ∈ V });
+ intros; simplify; apply (.= (e‡#)‡(e‡#)); apply refl1;
+ | intros;
+ split; intros 2; simplify in f ⊢ %;
+ [ apply (. (#‡e)‡(#‡e1)); assumption
+ | apply (. (#‡(e \sup -1))‡(#‡(e1 \sup -1))); assumption]]
+qed.
+
+interpretation "intersects" 'intersects U V = (fun21 ___ (intersects _) U V).
+
+definition union:
+ ∀A. binary_morphism1 (Ω \sup A) (Ω \sup A) (Ω \sup A).
+ intros;
+ constructor 1;
+ [ apply (λU,V. {x | x ∈ U ∨ x ∈ V });
+ intros; simplify; apply (.= (e‡#)‡(e‡#)); apply refl1
+ | intros;
+ split; intros 2; simplify in f ⊢ %;
+ [ apply (. (#‡e)‡(#‡e1)); assumption
+ | apply (. (#‡(e \sup -1))‡(#‡(e1 \sup -1))); assumption]]
+qed.
+
+interpretation "union" 'union U V = (fun21 ___ (union _) U V).
+
+definition singleton: ∀A:setoid. unary_morphism1 A (Ω \sup A).
+ intros; constructor 1;
+ [ apply (λa:A.{b | eq ? a b}); unfold setoid1_of_setoid; simplify;
+ intros; simplify;
+ split; intro;
+ apply (.= e1);
+ [ apply e | apply (e \sup -1) ]
+ | unfold setoid1_of_setoid; simplify;
+ intros; split; intros 2; simplify in f ⊢ %; apply trans;
+ [ apply a |4: apply a'] try assumption; apply sym; assumption]
+qed.
+
+interpretation "singleton" 'singl a = (fun11 __ (singleton _) a).
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