X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fmatita%2Fcontribs%2Fdama%2Fdama%2Fsupremum.ma;h=1e6c95b8dd4d5a3d0882dae2944fac70a29fac77;hb=5070f476ff80ee53fe444d284f9e7587a37022f4;hp=b99323140e3fd8a9423b142fade9a2b7a33a4114;hpb=b284579a0c4d45bc8483f295434a465ca685f444;p=helm.git

diff --git a/helm/software/matita/contribs/dama/dama/supremum.ma b/helm/software/matita/contribs/dama/dama/supremum.ma
index b99323140..1e6c95b8d 100644
--- a/helm/software/matita/contribs/dama/dama/supremum.ma
+++ b/helm/software/matita/contribs/dama/dama/supremum.ma
@@ -53,18 +53,12 @@ notation > "x 'is_supremum' s"  non associative with precedence 50
 notation > "x 'is_infimum' s"  non associative with precedence 50 
   for @{'infimum $s $x}.
 
-interpretation "Ordered set upper bound" 'upper_bound s x = 
-  (cic:/matita/dama/supremum/upper_bound.con _ s x).
-interpretation "Ordered set lower bound" 'lower_bound s x = 
-  (cic:/matita/dama/supremum/lower_bound.con _ s x).
-interpretation "Ordered set increasing"  'increasing s    = 
-  (cic:/matita/dama/supremum/increasing.con _ s).
-interpretation "Ordered set decreasing"  'decreasing s    = 
-  (cic:/matita/dama/supremum/decreasing.con _ s).
-interpretation "Ordered set strong sup"  'supremum s x  = 
-  (cic:/matita/dama/supremum/supremum.con _ s x).
-interpretation "Ordered set strong inf"  'infimum s x  = 
-  (cic:/matita/dama/supremum/infimum.con _ s x).
+interpretation "Ordered set upper bound" 'upper_bound s x = (upper_bound _ s x).
+interpretation "Ordered set lower bound" 'lower_bound s x = (lower_bound _ s x).
+interpretation "Ordered set increasing"  'increasing s    = (increasing _ s).
+interpretation "Ordered set decreasing"  'decreasing s    = (decreasing _ s).
+interpretation "Ordered set strong sup"  'supremum s x  = (supremum _ s x).
+interpretation "Ordered set strong inf"  'infimum s x  = (infimum _ s x).
   
 include "bishop_set.ma".
   
@@ -85,6 +79,14 @@ intros 7 (C s u Hu v Hv H); cases Hu (_ H1); clear Hu;
 cases (H1 ? H) (w Hw); apply Hv; assumption;
 qed.
 
+lemma infimum_is_lower_bound: 
+  ∀C:ordered_set.∀a:sequence C.∀u:C.
+   u is_infimum a → ∀v.v is_lower_bound a → v ≤ u.
+intros 7 (C s u Hu v Hv H); cases Hu (_ H1); clear Hu;
+cases (H1 ? H) (w Hw); apply Hv; assumption;
+qed.
+
+
 (* Lemma 2.6 *)
 definition strictly_increasing ≝ 
   λC:ordered_set.λa:sequence C.∀n:nat.a (S n) ≰ a n.
@@ -97,24 +99,29 @@ notation < "s \nbsp 'is_strictly_increasing'" non associative with precedence 50
 notation > "s 'is_strictly_increasing'" non associative with precedence 50 
   for @{'strictly_increasing $s}.
 interpretation "Ordered set strict increasing"  'strictly_increasing s    = 
-  (cic:/matita/dama/supremum/strictly_increasing.con _ s).
+  (strictly_increasing _ s).
 notation < "s \nbsp 'is_strictly_decreasing'" non associative with precedence 50 
   for @{'strictly_decreasing $s}.
 notation > "s 'is_strictly_decreasing'" non associative with precedence 50 
   for @{'strictly_decreasing $s}.
 interpretation "Ordered set strict decreasing"  'strictly_decreasing s    = 
-  (cic:/matita/dama/supremum/strictly_decreasing.con _ s).
-  
-notation "a \uparrow u" non associative with precedence 50 for @{'sup_inc $a $u}.
-interpretation "Ordered set supremum of increasing" 'sup_inc s u =
- (cic:/matita/dama/cprop_connectives/And.ind#xpointer(1/1) 
-  (cic:/matita/dama/supremum/increasing.con _ s)
-  (cic:/matita/dama/supremum/supremum.con _ s u)).
-notation "a \downarrow u" non associative with precedence 50 for @{'inf_dec $a $u}.
-interpretation "Ordered set supremum of increasing" 'inf_dec s u =
- (cic:/matita/dama/cprop_connectives/And.ind#xpointer(1/1) 
-  (cic:/matita/dama/supremum/decreasing.con _ s)
-  (cic:/matita/dama/supremum/infimum.con _ s u)).
+  (strictly_decreasing _ s).
+
+definition uparrow ≝
+  λC:ordered_set.λs:sequence C.λu:C.
+   s is_increasing ∧ u is_supremum s.
+   
+definition downarrow ≝
+  λC:ordered_set.λs:sequence C.λu:C.
+   s is_decreasing ∧ u is_infimum s.
+     
+notation < "a \uparrow \nbsp u" non associative with precedence 50 for @{'sup_inc $a $u}.
+notation > "a \uparrow u" non associative with precedence 50 for @{'sup_inc $a $u}.
+interpretation "Ordered set uparrow" 'sup_inc s u = (uparrow _ s u).
+
+notation < "a \downarrow \nbsp u" non associative with precedence 50 for @{'inf_dec $a $u}.
+notation > "a \downarrow u" non associative with precedence 50 for @{'inf_dec $a $u}.
+interpretation "Ordered set downarrow" 'inf_dec s u = (downarrow _ s u).
 
 include "nat/plus.ma".
 include "nat_ordered_set.ma".
@@ -132,6 +139,17 @@ cases (le_to_or_lt_eq ?? (not_lt_to_le (S n1) n H1)); clear H1;
     intro; whd in H1; apply (not_le_Sn_n n); apply (transitive_le ??? H2 H1);]
 qed.
 
+lemma trans_decreasing: 
+  ∀C:ordered_set.∀a:sequence C.a is_decreasing → ∀n,m:nat_ordered_set. n ≤ m → a m ≤ a n.
+intros 5 (C a Hs n m); elim m; [
+  rewrite > (le_n_O_to_eq n (not_lt_to_le O n H));
+  intro X; cases (os_coreflexive ?? X);]
+cases (le_to_or_lt_eq ?? (not_lt_to_le (S n1) n H1)); clear H1;
+[2: rewrite > H2; intro; cases (os_coreflexive ?? H1);
+|1: apply (le_transitive ???? (Hs ?) (H ?));
+    intro; whd in H1; apply (not_le_Sn_n n); apply (transitive_le ??? H2 H1);]
+qed.
+
 lemma trans_increasing_exc: 
   ∀C:ordered_set.∀a:sequence C.a is_increasing → ∀n,m:nat_ordered_set. m ≰ n → a n ≤ a m.
 intros 5 (C a Hs n m); elim m; [cases (not_le_Sn_O n H);]
@@ -144,6 +162,18 @@ intro; apply H;
     cases (Hs n1); assumption;]
 qed.
 
+lemma trans_decreasing_exc: 
+  ∀C:ordered_set.∀a:sequence C.a is_decreasing → ∀n,m:nat_ordered_set. m ≰ n → a m ≤ a n .
+intros 5 (C a Hs n m); elim m; [cases (not_le_Sn_O n H);]
+intro; apply H; 
+[1: change in n1 with (os_carr nat_ordered_set); (* canonical structures *) 
+    change with (n<n1); (* is sort elimination not allowed preserved by delta? *)
+    cases (le_to_or_lt_eq ?? H1); [apply le_S_S_to_le;assumption]
+    cases (Hs n); rewrite < H3 in H2; assumption (* ogni goal di tipo Prop non è anche di tipo CProp *)    
+|2: cases (os_cotransitive ??? (a n1) H2); [2:assumption]
+    cases (Hs n1); assumption;]
+qed.
+
 lemma strictly_increasing_reaches: 
   ∀C:ordered_set.∀m:sequence nat_ordered_set.
    m is_strictly_increasing → ∀w.∃t.m t ≰ w.
@@ -160,7 +190,7 @@ intros; elim w;
         apply (transitive_le ??? H2 Hp);]]
 qed.
      
-lemma selection: 
+lemma selection_uparrow: 
   ∀C:ordered_set.∀m:sequence nat_ordered_set.m is_strictly_increasing →
     ∀a:sequence C.∀u.a ↑ u → (λx.a (m x)) ↑ u.
 intros (C m Hm a u Ha); cases Ha (Ia Su); cases Su (Uu Hu); repeat split; 
@@ -171,22 +201,31 @@ intros (C m Hm a u Ha); cases Ha (Ia Su); cases Su (Uu Hu); repeat split;
     exists [apply w1]; cases (os_cotransitive ??? (a (m w1)) H); [2:assumption]  
     cases (trans_increasing_exc C ? Ia ?? H1); assumption;]
 qed.     
-    
+
+lemma selection_downarrow: 
+  ∀C:ordered_set.∀m:sequence nat_ordered_set.m is_strictly_increasing →
+    ∀a:sequence C.∀u.a ↓ u → (λx.a (m x)) ↓ u.
+intros (C m Hm a u Ha); cases Ha (Ia Su); cases Su (Uu Hu); repeat split; 
+[1: intro n; simplify; apply trans_decreasing_exc; [assumption] apply (Hm n);
+|2: intro n; simplify; apply Uu;
+|3: intros (y Hy); simplify; cases (Hu ? Hy);
+    cases (strictly_increasing_reaches C ? Hm w); 
+    exists [apply w1]; cases (os_cotransitive ??? (a (m w1)) H); [assumption]  
+    cases (trans_decreasing_exc C ? Ia ?? H1); assumption;]
+qed.     
+
 (* Definition 2.7 *)
-alias symbol "exists" = "CProp exists".
-alias symbol "and" = "constructive and".
+alias id "ExT23" = "cic:/matita/dama/cprop_connectives/exT23.ind#xpointer(1/1)".
 definition order_converge ≝
   λO:ordered_set.λa:sequence O.λx:O.
-   ∃l:sequence O.∃u:sequence O.
-    l is_increasing ∧ u is_decreasing ∧ l ↑ x ∧ u ↓ x ∧
-    ∀i:nat. (l i) is_infimum (λw.a (w+i)) ∧ (u i) is_supremum (λw.a (w+i)).
+   ExT23 (sequence O) (λl.l ↑ x) (λu.u ↓ x)
+     (λl,u.∀i:nat. (l i) is_infimum (λw.a (w+i)) ∧ (u i) is_supremum (λw.a (w+i))).
     
 notation < "a \nbsp (\circ \atop (\horbar\triangleright)) \nbsp x" non associative with precedence 50 
   for @{'order_converge $a $x}.
 notation > "a 'order_converges' x" non associative with precedence 50 
   for @{'order_converge $a $x}.
-interpretation "Order convergence" 'order_converge s u =
- (cic:/matita/dama/supremum/order_converge.con _ s u).   
+interpretation "Order convergence" 'order_converge s u = (order_converge _ s u).   
     
 (* Definition 2.8 *)
 
@@ -195,24 +234,17 @@ definition segment ≝ λO:ordered_set.λa,b:O.λx:O.
 
 notation "[a,b]" non associative with precedence 50 
   for @{'segment $a $b}.
-interpretation "Ordered set sergment" 'segment a b =
-  (cic:/matita/dama/supremum/segment.con _ a b).
+interpretation "Ordered set sergment" 'segment a b = (segment _ a b).
 
 notation "hvbox(x \in break [a,b])" non associative with precedence 50 
   for @{'segment2 $a $b $x}.
-interpretation "Ordered set sergment in" 'segment2 a b x=
-  (cic:/matita/dama/supremum/segment.con _ a b x).
+interpretation "Ordered set sergment in" 'segment2 a b x= (segment _ a b x).
 
 coinductive sigma (A:Type) (P:A→Prop) : Type ≝ sig_in : ∀x.P x → sigma A P.
 
 definition pi1 : ∀A.∀P.sigma A P → A ≝ λA,P,s.match s with [sig_in x _ ⇒ x].  
 
-notation < "'fst' \nbsp x" non associative with precedence 50 for @{'pi1 $x}.
-notation < "'snd' \nbsp x" non associative with precedence 50 for @{'pi2 $x}.
-notation > "'fst' x" non associative with precedence 50 for @{'pi1 $x}.
-notation > "'snd' x" non associative with precedence 50 for @{'pi2 $x}.
-interpretation "sigma pi1" 'pi1 x = 
- (cic:/matita/dama/supremum/pi1.con _ _ x).
+interpretation "sigma pi1" 'pi1 x = (pi1 _ _ x).
  
 interpretation "Type exists" 'exists \eta.x =
   (cic:/matita/dama/supremum/sigma.ind#xpointer(1/1) _ x).
@@ -228,7 +260,7 @@ qed.
 notation "hvbox({[a, break b]})" non associative with precedence 90 
   for @{'segment_set $a $b}.
 interpretation "Ordered set segment" 'segment_set a b = 
- (cic:/matita/dama/supremum/segment_ordered_set.con _ a b).
+ (segment_ordered_set _ a b).
 
 (* Lemma 2.9 *)
 lemma segment_preserves_supremum:
@@ -242,23 +274,31 @@ intros; split; cases H; clear H;
     |2: clear H; intro y0; apply (H3 (fst y0));]]
 qed.
 
+lemma segment_preserves_infimum:
+  ∀O:ordered_set.∀l,u:O.∀a:sequence {[l,u]}.∀x:{[l,u]}. 
+    (λn.fst (a n)) is_decreasing ∧ 
+    (fst x) is_infimum (λn.fst (a n)) → a ↓ x.
+intros; split; cases H; clear H; 
+[1: apply H1;
+|2: cases H2; split; clear H2;
+    [1: apply H;
+    |2: clear H; intro y0; apply (H3 (fst y0));]]
+qed.
+
+
 (* Definition 2.10 *)
 coinductive pair (A,B:Type) : Type ≝ prod : ∀a:A.∀b:B.pair A B. 
 definition first : ∀A.∀P.pair A P → A ≝ λA,P,s.match s with [prod x _ ⇒ x].
 definition second : ∀A.∀P.pair A P → P ≝ λA,P,s.match s with [prod _ y ⇒ y].
   
-interpretation "pair pi1" 'pi1 x = 
- (cic:/matita/dama/supremum/first.con _ _ x).
-interpretation "pair pi2" 'pi2 x = 
- (cic:/matita/dama/supremum/second.con _ _ x).
+interpretation "pair pi1" 'pi1 x = (first _ _ x).
+interpretation "pair pi2" 'pi2 x = (second _ _ x).
 
 notation "hvbox(\langle a, break b\rangle)" non associative with precedence 91 for @{ 'pair $a $b}.
-interpretation "pair" 'pair a b = 
- (cic:/matita/dama/supremum/pair.ind#xpointer(1/1/1) _ _ a b).
+interpretation "pair" 'pair a b = (prod _ _ a b).
  
 notation "a \times b" left associative with precedence 60 for @{'prod $a $b}.
-interpretation "prod" 'prod a b = 
- (cic:/matita/dama/supremum/pair.ind#xpointer(1/1) a b).
+interpretation "prod" 'prod a b = (pair a b).
  
 lemma square_ordered_set: ordered_set → ordered_set.
 intro O; apply (mk_ordered_set (O × O));
@@ -275,8 +315,7 @@ notation < "s  2 \atop \nleq" non associative with precedence 90
   for @{ 'square $s }.
 notation > "s 'square'" non associative with precedence 90
   for @{ 'square $s }.
-interpretation "ordered set square" 'square s = 
- (cic:/matita/dama/supremum/square_ordered_set.con s).
+interpretation "ordered set square" 'square s = (square_ordered_set s).
  
 definition square_segment ≝ 
   λO:ordered_set.λa,b:O.λx:square_ordered_set O.
@@ -302,14 +341,14 @@ notation < "s \nbsp 'is_upper_located'" non associative with precedence 50
 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).
+  (upper_located _ 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).
+  (lower_located _ s).
     
 (* Lemma 2.12 *)    
 lemma uparrow_upperlocated:
@@ -327,5 +366,3 @@ 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