interpretation "constructive and" 'and x y = (And x y).
+inductive Or (A,B:CProp) : CProp ≝
+ | or_intro_l: A → Or A B
+ | or_intro_r: B → Or A B.
+
+interpretation "constructive or" 'or x y = (Or x y).
+
inductive exT2 (A:Type) (P,Q:A→CProp) : CProp ≝
ex_introT2: ∀w:A. P w → Q w → exT2 A P Q.
interpretation "powerset" 'powerset A = (powerset A).
+notation < "hvbox({ ident i | term 19 p })" with precedence 90
+for @{ 'subset (\lambda ${ident i} : $nonexistent . $p)}.
+
+notation > "hvbox({ ident i | term 19 p })" with precedence 90
+for @{ 'subset (\lambda ${ident i}. $p)}.
+
+interpretation "subset construction" 'subset \eta.x = (mk_powerset _ x).
+
definition mem ≝ λA.λS:2 \sup A.λx:A. match S with [mk_powerset c ⇒ c x].
notation "hvbox(a break ∈ b)" non associative with precedence 45
interpretation "mem" 'mem a S = (mem _ S a).
-record axiom_set : Type ≝
- { A:> Type;
- i: A → Type;
- C: ∀a:A. i a → 2 \sup A
- }.
+definition overlaps ≝ λA:Type.λU,V:2 \sup A.exT2 ? (λa:A. a ∈ U) (λa.a ∈ V).
+
+notation "hvbox(a break ≬ b)" non associative with precedence 45
+for @{ 'overlaps $a $b }. (* \between *)
+
+interpretation "overlaps" 'overlaps U V = (overlaps _ U V).
+
+definition subseteq ≝ λA:Type.λU,V:2 \sup A.∀a:A. a ∈ U → a ∈ V.
+
+notation "hvbox(a break ⊆ b)" non associative with precedence 45
+for @{ 'subseteq $a $b }. (* \subseteq *)
+
+interpretation "subseteq" 'subseteq U V = (subseteq _ U V).
+
+definition intersects ≝ λA:Type.λU,V:2 \sup A.{a | a ∈ U ∧ a ∈ V}.
+
+notation "hvbox(a break ∩ b)" non associative with precedence 55
+for @{ 'intersects $a $b }. (* \cap *)
+
+interpretation "intersects" 'intersects U V = (intersects _ U V).
+
+definition union ≝ λA:Type.λU,V:2 \sup A.{a | a ∈ U ∨ a ∈ V}.
+
+notation "hvbox(a break ∪ b)" non associative with precedence 55
+for @{ 'union $a $b }. (* \cup *)
+
+interpretation "union" 'union U V = (union _ U V).
+
+record axiom_set : Type ≝ {
+ A:> Type;
+ i: A → Type;
+ C: ∀a:A. i a → 2 \sup A
+}.
inductive for_all (A: axiom_set) (U,V: 2 \sup A) (covers: A → CProp) : CProp ≝
iter: (∀a:A.a ∈ V → covers a) → for_all A U V covers.
definition covers_elim ≝
λA:axiom_set.λU: 2 \sup A.λP:2 \sup A.
λH1:∀a:A. a ∈ U → a ∈ P.
- λH2:∀a:A.∀j:i ? a. C ? a j ◃ U → (∀b. b ∈ C ? a j → b ∈ P) → a ∈ P.
+ λH2:∀a:A.∀j:i ? a. C ? a j ◃ U → C ? a j ⊆ P → a ∈ P.
let rec aux (a:A) (p:a ◃ U) on p : a ∈ P ≝
match p return λaa.λ_:aa ◃ U.aa ∈ P with
[ refl a q ⇒ H1 a q
| infinity a j q ⇒
H2 a j q
- match q return λ_:(C ? a j) ◃ U.∀b. b ∈ (C ? a j) → b ∈ P with
+ match q return λ_:(C ? a j) ◃ U. C ? a j ⊆ P with
[ iter f ⇒ λb.λr. aux b (f b r) ]]
in
aux.
let corec fish_rec (A:axiom_set) (U: 2 \sup A)
(P: 2 \sup A) (H1: ∀a:A. a ∈ P → a ∈ U)
- (H2: ∀a:A. a ∈ P → ∀j: i ? a. exT2 ? (λy.y ∈ C ? a j) (λy.y ∈ P)) :
+ (H2: ∀a:A. a ∈ P → ∀j: i ? a. C ? a j ≬ P):
∀a:A. ∀p: a ∈ P. a ⋉ U ≝
λa,p.
mk_fish A U a
theorem transitivity: ∀A:axiom_set.∀a:A.∀U,V. a ◃ U → U ◃ V → a ◃ V.
intros;
- apply (covers_elim ?? (mk_powerset A (λa.a ◃ V)) ??? H); simplify; intros;
+ apply (covers_elim ?? {a | a ◃ V} ??? H); simplify; intros;
[ cases H1 in H2; apply H2;
| apply infinity;
[ assumption
theorem cotransitivity:
∀A:axiom_set.∀a:A.∀U,V. a ⋉ U → (∀b:A. b ⋉ U → b ∈ V) → a ⋉ V.
intros;
- apply (fish_rec ?? (mk_powerset A (λa.a ⋉ U)) ??? H); simplify; intros;
+ apply (fish_rec ?? {a|a ⋉ U} ??? H); simplify; intros;
[ apply H1; apply H2;
| cases H2 in j; clear H2; intro i;
cases (H4 i); clear H4; exists[apply a3] assumption]
theorem compatibility: ∀A:axiom_set.∀a:A.∀U,V. a ⋉ V → a ◃ U → U ⋉ V.
intros;
generalize in match H; clear H;
- apply (covers_elim ?? (mk_powerset A (λa.a ⋉ V → U ⋉ V)) ??? H1);
+ apply (covers_elim ?? {a|a ⋉ V → U ⋉ V} ??? H1);
clear H1; simplify; intros;
[ exists [apply a1] assumption
| cases H2 in j H H1; clear H2 a1; intros;
cases (H1 i); clear H1; apply (H3 a1); assumption]
qed.
-definition singleton ≝ λA:axiom_set.λa:A.mk_powerset ? (λb:A.a=b).
+definition singleton ≝ λA:axiom_set.λa:A.{b | a=b}.
notation "hvbox({ term 19 a })" with precedence 90 for @{ 'singl $a}.
interpretation "uparrow" 'uparrow a = (uparrow _ a).
-definition overlaps ≝ λA:Type.λU,V:2 \sup A.exT2 ? (λa:A. a ∈ U) (λa.a ∈ V).
-
-notation "hvbox(a break ≬ b)" non associative with precedence 45
-for @{ 'overlaps $a $b }.
-
-interpretation "overlaps" 'overlaps U V = (overlaps _ U V).
-
-definition intersects ≝ λA:Type.λU,V:2 \sup A.mk_powerset ? (λa:A. a ∈ U ∧ a ∈ V).
-
-notation "hvbox(a break ∩ b)" non associative with precedence 55
-for @{ 'intersects $a $b }.
-
-interpretation "intersects" 'intersects U V = (intersects _ U V).
-
definition downarrow ≝ λA:axiom_set.λU:2 \sup A.mk_powerset ? (λa:A. ↑a ≬ U).
notation "↓a" with precedence 80 for @{ 'downarrow $a }.