(a is_increasing → a is_upper_located → a is_cauchy) ∧
(b is_decreasing → b is_lower_located → b is_cauchy).
-lemma segment_upperbound:
- ∀C:ordered_set.∀l,u:C.∀a:sequence {[l,u]}.u is_upper_bound ⌊n,\fst (a n)⌋.
-intros 5; change with (\fst (a n) ≤ u); cases (a n); cases H; assumption;
+lemma h_segment_upperbound:
+ ∀C:half_ordered_set.
+ ∀s:segment C.
+ ∀a:sequence (half_segment_ordered_set C s).
+ (seg_u C s) (upper_bound ? ⌊n,\fst (a n)⌋).
+intros; cases (wloss_prop C); unfold; rewrite < H; simplify; intro n;
+cases (a n); simplify; unfold in H1; rewrite < H in H1; cases H1;
+simplify in H2 H3; rewrite < H in H2 H3; assumption;
qed.
-lemma segment_lowerbound:
- ∀C:ordered_set.∀l,u:C.∀a:sequence {[l,u]}.l is_lower_bound ⌊n,\fst (a n)⌋.
-intros 5; change with (l ≤ \fst (a n)); cases (a n); cases H; assumption;
-qed.
+notation "'segment_upperbound'" non associative with precedence 90 for @{'segment_upperbound}.
+notation "'segment_lowerbound'" non associative with precedence 90 for @{'segment_lowerbound}.
-lemma segment_preserves_uparrow:
- ∀C:ordered_set.∀l,u:C.∀a:sequence {[l,u]}.∀x,h.
- ⌊n,\fst (a n)⌋ ↑ x → a ↑ ≪x,h≫.
-intros; cases H (Ha Hx); split [apply Ha] cases Hx;
-split; [apply H1] intros;
-cases (H2 (\fst y)); [2: apply H3;] exists [apply w] assumption;
-qed.
+interpretation "segment_upperbound" 'segment_upperbound = (h_segment_upperbound (os_l _)).
+interpretation "segment_lowerbound" 'segment_lowerbound = (h_segment_upperbound (os_r _)).
-lemma segment_preserves_downarrow:
- ∀C:ordered_set.∀l,u:C.∀a:sequence {[l,u]}.∀x,h.
- ⌊n,\fst (a n)⌋ ↓ x → a ↓ ≪x,h≫.
-intros; cases H (Ha Hx); split [apply Ha] cases Hx;
-split; [apply H1] intros;
-cases (H2 (\fst y));[2:apply H3]; exists [apply w] assumption;
+lemma h_segment_preserves_uparrow:
+ ∀C:half_ordered_set.∀s:segment C.∀a:sequence (half_segment_ordered_set C s).
+ ∀x,h. uparrow C ⌊n,\fst (a n)⌋ x → uparrow (half_segment_ordered_set C s) a ≪x,h≫.
+intros; cases H (Ha Hx); split;
+[ intro n; intro H; apply (Ha n); apply (sx2x ???? H);
+| cases Hx; split;
+ [ intro n; intro H; apply (H1 n);apply (sx2x ???? H);
+ | intros; cases (H2 (\fst y)); [2: apply (sx2x ???? H3);]
+ exists [apply w] apply (x2sx ?? (a w) y H4);]]
qed.
-
+
+notation "'segment_preserves_uparrow'" non associative with precedence 90 for @{'segment_preserves_uparrow}.
+notation "'segment_preserves_downarrow'" non associative with precedence 90 for @{'segment_preserves_downarrow}.
+
+interpretation "segment_preserves_uparrow" 'segment_preserves_uparrow = (h_segment_preserves_uparrow (os_l _)).
+interpretation "segment_preserves_downarrow" 'segment_preserves_downarrow = (h_segment_preserves_uparrow (os_r _)).
+
+lemma hint_pippo:
+ ∀C,s.
+ sequence
+ (Type_of_ordered_set
+ (segment_ordered_set
+ (ordered_set_OF_ordered_uniform_space C) s))
+ →
+ sequence (Type_OF_uniform_space (segment_ordered_uniform_space C s)). intros; assumption;
+qed.
+
+coercion hint_pippo nocomposites.
+
(* Fact 2.18 *)
lemma segment_cauchy:
- ∀C:ordered_uniform_space.∀l,u:C.∀a:sequence {[l,u]}.
+ ∀C:ordered_uniform_space.∀s:‡C.∀a:sequence {[s]}.
a is_cauchy → ⌊n,\fst (a n)⌋ is_cauchy.
-intros 7;
+intros 6;
alias symbol "pi1" (instance 3) = "pair pi1".
alias symbol "pi2" = "pair pi2".
-apply (H (λx:{[l,u]} squareB.U 〈\fst (\fst x),\fst (\snd x)〉));
+apply (H (λx:{[s]} squareB.U 〈\fst (\fst x),\fst (\snd x)〉));
(unfold segment_ordered_uniform_space; simplify);
exists [apply U] split; [assumption;]
intro; cases b; intros; simplify; split; intros; assumption;