+sandwich.ma ordered_uniform.ma
+property_sigma.ma ordered_uniform.ma
+uniform.ma supremum.ma
bishop_set.ma ordered_set.ma
-extra.ma bishop_set_rewrite.ma
-ordered_set.ma cprop_connectives.ma
-cprop_connectives.ma logic/equality.ma
-bishop_set_rewrite.ma bishop_set.ma
sequence.ma nat/nat.ma
-uniform.ma supremum.ma
+ordered_uniform.ma uniform.ma
supremum.ma bishop_set.ma cprop_connectives.ma nat/plus.ma nat_ordered_set.ma ordered_set.ma sequence.ma
+property_exhaustivity.ma ordered_uniform.ma
+bishop_set_rewrite.ma bishop_set.ma
+cprop_connectives.ma logic/equality.ma
nat_ordered_set.ma cprop_connectives.ma nat/compare.ma ordered_set.ma
-property_sigma.ma ordered_uniform.ma
-ordered_uniform.ma uniform.ma
-sandwich.ma ordered_uniform.ma
+ordered_set.ma cprop_connectives.ma
+extra.ma bishop_set_rewrite.ma
logic/equality.ma
nat/compare.ma
nat/nat.ma
--- /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 "ordered_uniform.ma".
+
+(* Definition 3.7 *)
+definition exhaustivity ≝
+ λC:ordered_uniform_space.
+ ∀a,b:sequence C.
+ (a is_increasing → a is_upper_located → a is_cauchy) ∧
+ (b is_decreasing → b is_lower_located → b is_cauchy).
+
+(* Lemma 3.8 *)
definition upper_located ≝
λO:ordered_set.λa:sequence O.∀x,y:O. y ≰ x →
(∃i:nat.a i ≰ x) ∨ (∃b:O.y≰b ∧ ∀i:nat.a i ≤ b).
+
+definition lower_located ≝
+ λO:ordered_set.λa:sequence O.∀x,y:O. x ≰ y →
+ (∃i:nat.x ≰ a i) ∨ (∃b:O.b≰y ∧ ∀i:nat.b ≤ a i).
+
+notation < "s \nbsp 'is_upper_located'" non associative with precedence 50
+ for @{'upper_located $s}.
+notation > "s 'is_upper_located'" non associative with precedence 50
+ for @{'upper_located $s}.
+interpretation "Ordered set upper locatedness" 'upper_located s =
+ (cic:/matita/dama/supremum/upper_located.con _ s).
+
+notation < "s \nbsp 'is_lower_located'" non associative with precedence 50
+ for @{'lower_located $s}.
+notation > "s 'is_lower_located'" non associative with precedence 50
+ for @{'lower_located $s}.
+interpretation "Ordered set lower locatedness" 'lower_located s =
+ (cic:/matita/dama/supremum/lower_located.con _ s).
(* Lemma 2.12 *)
-lemma uparrow_located:
- ∀C:ordered_set.∀a:sequence C.∀u:C.a ↑ u → upper_located ? a.
+lemma uparrow_upperlocated:
+ ∀C:ordered_set.∀a:sequence C.∀u:C.a ↑ u → a is_upper_located.
intros (C a u H); cases H (H2 H3); clear H; intros 3 (x y Hxy);
cases H3 (H4 H5); clear H3; cases (os_cotransitive ??? u Hxy) (W W);
[2: cases (H5 ? W) (w Hw); left; exists [apply w] assumption;
|1: right; exists [apply u]; split; [apply W|apply H4]]
qed.
+lemma downarrow_lowerlocated:
+ ∀C:ordered_set.∀a:sequence C.∀u:C.a ↓ u → a is_lower_located.
+intros (C a u H); cases H (H2 H3); clear H; intros 3 (x y Hxy);
+cases H3 (H4 H5); clear H3; cases (os_cotransitive ??? u Hxy) (W W);
+[1: cases (H5 ? W) (w Hw); left; exists [apply w] assumption;
+|2: right; exists [apply u]; split; [apply W|apply H4]]
+qed.
\ No newline at end of file