(* *)
(**************************************************************************)
-include "datatypes/subsets.ma".
+include "logic/equality.ma".
+include "logic/cprop_connectives.ma".
+
+record powerset (A : Type) : Type ≝ { char : A → CProp }.
+
+interpretation "char" 'subset p = (mk_powerset _ p).
+
+interpretation "pwset" 'powerset a = (powerset a).
+
+interpretation "in" 'mem a X = (char _ X a).
+
+definition subseteq ≝ λA.λu,v:\Omega \sup A.∀x.x ∈ u → x ∈ v.
+
+interpretation "subseteq" 'subseteq u v = (subseteq _ u v).
+
+definition overlaps ≝ λA.λU,V : Ω \sup A. exT2 ? (λx.x ∈ U) (λx.x ∈ V).
+
+interpretation "overlaps" 'overlaps u v = (overlaps _ u v).
+
+definition intersect ≝ λA.λu,v:Ω\sup A.{ y | y ∈ u ∧ y ∈ v }.
+
+interpretation "intersect" 'intersects u v = (intersect _ u v).
record axiom_set : Type ≝ {
A:> Type;
assumption]]
qed.
+theorem covers_elim2:
+ ∀A: axiom_set. ∀U:Ω \sup A.∀P: A → CProp.
+ (∀a:A. a ∈ U → P a) →
+ (∀a:A.∀V:Ω \sup A. a ◃ V → V ◃ U → (∀y. y ∈ V → P y) → P a) →
+ ∀a:A. a ◃ U → P a.
+ intros;
+ change with (a ∈ {a | P a});
+ apply (covers_elim ?????? H2);
+ [ intros 2; simplify; apply H; assumption
+ | intros;
+ simplify in H4 ⊢ %;
+ apply H1;
+ [ apply (C ? a1 j);
+ | autobatch;
+ | assumption;
+ | assumption]]
+qed.
+
theorem coreflexivity: ∀A:axiom_set.∀a:A.∀V. a ⋉ V → a ∈ V.
intros;
cases H;
generalize in match H; clear H;
apply (covers_elim ?? {a|a ⋉ V → U ⋉ V} ??? H1);
clear H1; simplify; intros;
- [ exists [apply a1] assumption
+ [ exists [apply x] assumption
| cases H2 in j H H1; clear H2 a1; intros;
cases (H1 i); clear H1; apply (H3 a1); assumption]
qed.
-definition leq ≝ λA:axiom_set.λa,b:A. a ◃ {b}.
+definition leq ≝ λA:axiom_set.λa,b:A. a ◃ {y|b=y}.
interpretation "covered by one" 'leq a b = (leq _ a b).
definition uparrow ≝ λA:axiom_set.λa:A.mk_powerset ? (λb:A. a ≤ b).
-notation "↑a" with precedence 80 for @{ 'uparrow $a }.
-
interpretation "uparrow" 'uparrow a = (uparrow _ a).
-definition downarrow ≝ λA:axiom_set.λU:Ω \sup A.mk_powerset ? (λa:A. ↑a ≬ U).
-
-notation "↓a" with precedence 80 for @{ 'downarrow $a }.
+definition downarrow ≝ λA:axiom_set.λU:Ω \sup A.mk_powerset ? (λa:A. (↑a) ≬ U).
interpretation "downarrow" 'downarrow a = (downarrow _ a).
record convergent_generated_topology : Type ≝
{ AA:> axiom_set;
- convergence: ∀a:AA.∀U,V:Ω \sup AA. a ◃ U → a ◃ V → a ◃ U ↓ V
+ convergence: ∀a:AA.∀U,V:Ω \sup AA. a ◃ U → a ◃ V → a ◃ (U ↓ V)
}.
-