X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fdama%2Fordered_sets.ma;h=946d89573242cbea8907e867816645e256671e22;hb=f2b44fbe63263f5ed70d251304f0df670302182f;hp=1ca191339b697514c39b171ed9111ef8c6a1003c;hpb=810db29f760117d933ee1f74328043b8fce43847;p=helm.git

diff --git a/matita/dama/ordered_sets.ma b/matita/dama/ordered_sets.ma
index 1ca191339..946d89573 100644
--- a/matita/dama/ordered_sets.ma
+++ b/matita/dama/ordered_sets.ma
@@ -14,682 +14,201 @@
 
 set "baseuri" "cic:/matita/ordered_sets/".
 
-include "higher_order_defs/relations.ma".
-include "nat/plus.ma".
-include "constructive_connectives.ma".
-
-definition cotransitive ≝
- λC:Type.λle:C→C→Prop.∀x,y,z:C. le x y → le x z ∨ le z y. 
-
-definition antisimmetric ≝
- λC:Type.λle:C→C→Prop.∀x,y:C. le x y → le y x → x=y.
-
-record is_order_relation (C:Type) (le:C→C→Prop) : Type ≝
- { or_reflexive: reflexive ? le;
-   or_transitive: transitive ? le;
-   or_antisimmetric: antisimmetric ? le
- }.
-
-record ordered_set: Type ≝
- { os_carrier:> Type;
-   os_le: os_carrier → os_carrier → Prop;
-   os_order_relation_properties:> is_order_relation ? os_le
- }.
+include "excedence.ma".
+
+record is_porder_relation (C:Type) (le:C→C→Prop) (eq:C→C→Prop) : Type ≝ { 
+  por_reflexive: reflexive ? le;
+  por_transitive: transitive ? le;
+  por_antisimmetric: antisymmetric ? le eq
+}.
+
+record pordered_set: Type ≝ { 
+  pos_carr:> excedence;
+  pos_order_relation_properties:> is_porder_relation ? (le pos_carr) (eq pos_carr)
+}.
+
+lemma pordered_set_of_excedence: excedence → pordered_set.
+intros (E); apply (mk_pordered_set E); apply (mk_is_porder_relation);
+[apply le_reflexive|apply le_transitive|apply le_antisymmetric]
+qed. 
 
-interpretation "Ordered Sets le" 'leq a b =
- (cic:/matita/ordered_sets/os_le.con _ a b).
+alias id "transitive" = "cic:/matita/higher_order_defs/relations/transitive.con".
+alias id "cotransitive" = "cic:/matita/higher_order_defs/relations/cotransitive.con".
+alias id "antisymmetric" = "cic:/matita/higher_order_defs/relations/antisymmetric.con".
 
 theorem antisimmetric_to_cotransitive_to_transitive:
- ∀C.∀le:relation C. antisimmetric ? le → cotransitive ? le →
-  transitive ? le.
- intros;
- unfold transitive;
- intros;
- elim (c ? ? z H1);
-  [ assumption
-  | rewrite < (H ? ? H2 t);
-    assumption
-  ].
+ ∀C:Type.∀le:C→C→Prop. antisymmetric ? le → cotransitive ? le → transitive ? le.  
+intros (T f Af cT); unfold transitive; intros (x y z fxy fyz);
+lapply (cT ? ? fxy z) as H; cases H; [assumption] cases (Af ? ? fyz H1);
 qed.
 
-definition is_increasing ≝ λO:ordered_set.λa:nat→O.∀n:nat.a n ≤ a (S n).
-definition is_decreasing ≝ λO:ordered_set.λa:nat→O.∀n:nat.a (S n) ≤ a n.
+definition is_increasing ≝ λO:pordered_set.λa:nat→O.∀n:nat.a n ≤ a (S n).
+definition is_decreasing ≝ λO:pordered_set.λa:nat→O.∀n:nat.a (S n) ≤ a n.
 
-definition is_upper_bound ≝ λO:ordered_set.λa:nat→O.λu:O.∀n:nat.a n ≤ u.
-definition is_lower_bound ≝ λO:ordered_set.λa:nat→O.λu:O.∀n:nat.u ≤ a n.
+definition is_upper_bound ≝ λO:pordered_set.λa:nat→O.λu:O.∀n:nat.a n ≤ u.
+definition is_lower_bound ≝ λO:pordered_set.λa:nat→O.λu:O.∀n:nat.u ≤ a n.
 
-record is_sup (O:ordered_set) (a:nat→O) (u:O) : Prop ≝
+record is_sup (O:pordered_set) (a:nat→O) (u:O) : Prop ≝
  { sup_upper_bound: is_upper_bound O a u; 
    sup_least_upper_bound: ∀v:O. is_upper_bound O a v → u≤v
  }.
 
-record is_inf (O:ordered_set) (a:nat→O) (u:O) : Prop ≝
+record is_inf (O:pordered_set) (a:nat→O) (u:O) : Prop ≝
  { inf_lower_bound: is_lower_bound O a u; 
    inf_greatest_lower_bound: ∀v:O. is_lower_bound O a v → v≤u
  }.
 
-record is_bounded_below (O:ordered_set) (a:nat→O) : Type ≝
+record is_bounded_below (O:pordered_set) (a:nat→O) : Type ≝
  { ib_lower_bound: O;
    ib_lower_bound_is_lower_bound: is_lower_bound ? a ib_lower_bound
  }.
 
-record is_bounded_above (O:ordered_set) (a:nat→O) : Type ≝
+record is_bounded_above (O:pordered_set) (a:nat→O) : Type ≝
  { ib_upper_bound: O;
    ib_upper_bound_is_upper_bound: is_upper_bound ? a ib_upper_bound
  }.
 
-record is_bounded (O:ordered_set) (a:nat→O) : Type ≝
+record is_bounded (O:pordered_set) (a:nat→O) : Type ≝
  { ib_bounded_below:> is_bounded_below ? a;
    ib_bounded_above:> is_bounded_above ? a
  }.
 
-record bounded_below_sequence (O:ordered_set) : Type ≝
+record bounded_below_sequence (O:pordered_set) : Type ≝
  { bbs_seq:1> nat→O;
    bbs_is_bounded_below:> is_bounded_below ? bbs_seq
  }.
 
-record bounded_above_sequence (O:ordered_set) : Type ≝
+record bounded_above_sequence (O:pordered_set) : Type ≝
  { bas_seq:1> nat→O;
    bas_is_bounded_above:> is_bounded_above ? bas_seq
  }.
 
-record bounded_sequence (O:ordered_set) : Type ≝
+record bounded_sequence (O:pordered_set) : Type ≝
  { bs_seq:1> nat → O;
    bs_is_bounded_below: is_bounded_below ? bs_seq;
    bs_is_bounded_above: is_bounded_above ? bs_seq
  }.
 
 definition bounded_below_sequence_of_bounded_sequence ≝
- λO:ordered_set.λb:bounded_sequence O.
+ λO:pordered_set.λb:bounded_sequence O.
   mk_bounded_below_sequence ? b (bs_is_bounded_below ? b).
 
 coercion cic:/matita/ordered_sets/bounded_below_sequence_of_bounded_sequence.con.
 
 definition bounded_above_sequence_of_bounded_sequence ≝
- λO:ordered_set.λb:bounded_sequence O.
+ λO:pordered_set.λb:bounded_sequence O.
   mk_bounded_above_sequence ? b (bs_is_bounded_above ? b).
 
 coercion cic:/matita/ordered_sets/bounded_above_sequence_of_bounded_sequence.con.
 
 definition lower_bound ≝
- λO:ordered_set.λb:bounded_below_sequence O.
+ λO:pordered_set.λb:bounded_below_sequence O.
   ib_lower_bound ? b (bbs_is_bounded_below ? b).
 
 lemma lower_bound_is_lower_bound:
- ∀O:ordered_set.∀b:bounded_below_sequence O.
+ ∀O:pordered_set.∀b:bounded_below_sequence O.
   is_lower_bound ? b (lower_bound ? b).
- intros;
- unfold lower_bound;
- apply ib_lower_bound_is_lower_bound.
+intros; unfold lower_bound; apply ib_lower_bound_is_lower_bound.
 qed.
 
 definition upper_bound ≝
- λO:ordered_set.λb:bounded_above_sequence O.
+ λO:pordered_set.λb:bounded_above_sequence O.
   ib_upper_bound ? b (bas_is_bounded_above ? b).
 
 lemma upper_bound_is_upper_bound:
- ∀O:ordered_set.∀b:bounded_above_sequence O.
+ ∀O:pordered_set.∀b:bounded_above_sequence O.
   is_upper_bound ? b (upper_bound ? b).
- intros;
- unfold upper_bound;
- apply ib_upper_bound_is_upper_bound.
+intros; unfold upper_bound; apply ib_upper_bound_is_upper_bound.
 qed.
 
-record is_dedekind_sigma_complete (O:ordered_set) : Type ≝
- { dsc_inf: ∀a:nat→O.∀m:O. is_lower_bound ? a m → ex ? (λs:O.is_inf O a s);
-   dsc_inf_proof_irrelevant:
-    ∀a:nat→O.∀m,m':O.∀p:is_lower_bound ? a m.∀p':is_lower_bound ? a m'.
-     (match dsc_inf a m p with [ ex_intro s _ ⇒ s ]) =
-     (match dsc_inf a m' p' with [ ex_intro s' _ ⇒ s' ]); 
-   dsc_sup: ∀a:nat→O.∀m:O. is_upper_bound ? a m → ex ? (λs:O.is_sup O a s);
-   dsc_sup_proof_irrelevant:
-    ∀a:nat→O.∀m,m':O.∀p:is_upper_bound ? a m.∀p':is_upper_bound ? a m'.
-     (match dsc_sup a m p with [ ex_intro s _ ⇒ s ]) =
-     (match dsc_sup a m' p' with [ ex_intro s' _ ⇒ s' ])    
- }.
-
-record dedekind_sigma_complete_ordered_set : Type ≝
- { dscos_ordered_set:> ordered_set;
-   dscos_dedekind_sigma_complete_properties:>
-    is_dedekind_sigma_complete dscos_ordered_set
- }.
-
-definition inf:
- ∀O:dedekind_sigma_complete_ordered_set.
-  bounded_below_sequence O → O.
- intros;
- elim
-  (dsc_inf O (dscos_dedekind_sigma_complete_properties O) b);
-  [ apply a
-  | apply (lower_bound ? b)
-  | apply lower_bound_is_lower_bound
-  ]
+lemma Or_symmetric: symmetric ? Or.
+unfold; intros (x y H); cases H; [right|left] assumption;
 qed.
 
-lemma inf_is_inf:
- ∀O:dedekind_sigma_complete_ordered_set.
-  ∀a:bounded_below_sequence O.
-   is_inf ? a (inf ? a).
- intros;
- unfold inf;
- simplify;
- elim (dsc_inf O (dscos_dedekind_sigma_complete_properties O) a
-(lower_bound O a) (lower_bound_is_lower_bound O a));
- simplify;
- assumption.
-qed.
-
-lemma inf_proof_irrelevant:
- ∀O:dedekind_sigma_complete_ordered_set.
-  ∀a,a':bounded_below_sequence O.
-   bbs_seq ? a = bbs_seq ? a' →
-    inf ? a = inf ? a'.
- intros 3;
- elim a 0;
- elim a';
- simplify in H;
- generalize in match i1;
- clear i1;
- rewrite > H;
- intro;
- simplify;
- rewrite < (dsc_inf_proof_irrelevant O O f (ib_lower_bound ? f i)
-  (ib_lower_bound ? f i2) (ib_lower_bound_is_lower_bound ? f i)
-  (ib_lower_bound_is_lower_bound ? f i2));
- reflexivity.
-qed.
-
-definition sup:
- ∀O:dedekind_sigma_complete_ordered_set.
-  bounded_above_sequence O → O.
- intros;
- elim
-  (dsc_sup O (dscos_dedekind_sigma_complete_properties O) b);
-  [ apply a
-  | apply (upper_bound ? b)
-  | apply upper_bound_is_upper_bound
-  ].
-qed.
-
-lemma sup_is_sup:
- ∀O:dedekind_sigma_complete_ordered_set.
-  ∀a:bounded_above_sequence O.
-   is_sup ? a (sup ? a).
- intros;
- unfold sup;
- simplify;
- elim (dsc_sup O (dscos_dedekind_sigma_complete_properties O) a
-(upper_bound O a) (upper_bound_is_upper_bound O a));
- simplify;
- assumption.
-qed.
-
-lemma sup_proof_irrelevant:
- ∀O:dedekind_sigma_complete_ordered_set.
-  ∀a,a':bounded_above_sequence O.
-   bas_seq ? a = bas_seq ? a' →
-    sup ? a = sup ? a'.
- intros 3;
- elim a 0;
- elim a';
- simplify in H;
- generalize in match i1;
- clear i1;
- rewrite > H;
- intro;
- simplify;
- rewrite < (dsc_sup_proof_irrelevant O O f (ib_upper_bound ? f i2)
-  (ib_upper_bound ? f i) (ib_upper_bound_is_upper_bound ? f i2)
-  (ib_upper_bound_is_upper_bound ? f i));
- reflexivity.
-qed.
-
-axiom daemon: False.
-
-theorem inf_le_sup:
- ∀O:dedekind_sigma_complete_ordered_set.
-  ∀a:bounded_sequence O. inf ? a ≤ sup ? a.
- intros (O');
- apply (or_transitive ? ? O' ? (a O));
-  [ elim daemon (*apply (inf_lower_bound ? ? ? ? (inf_is_inf ? ? a))*)
-  | elim daemon (*apply (sup_upper_bound ? ? ? ? (sup_is_sup ? ? a))*)
-  ].
-qed.
-
-lemma inf_respects_le:
- ∀O:dedekind_sigma_complete_ordered_set.
-  ∀a:bounded_below_sequence O.∀m:O.
-   is_upper_bound ? a m → inf ? a ≤ m.
- intros (O');
- apply (or_transitive ? ? O' ? (sup ? (mk_bounded_sequence ? a ? ?)));
-  [ apply (bbs_is_bounded_below ? a)
-  | apply (mk_is_bounded_above ? ? m H)
-  | apply inf_le_sup 
-  | apply
-     (sup_least_upper_bound ? ? ?
-      (sup_is_sup ? (mk_bounded_sequence O' a a
-        (mk_is_bounded_above O' a m H))));
-    assumption
-  ].
+definition reverse_excedence: excedence → excedence.
+intros (E); apply (mk_excedence E); [apply (λx,y.exc_relation E y x)] 
+cases E (T f cRf cTf); simplify; 
+[1: unfold Not; intros (x H); apply (cRf x); assumption
+|2: intros (x y z); apply Or_symmetric; apply cTf; assumption;]
 qed. 
 
-definition is_sequentially_monotone ≝
- λO:ordered_set.λf:O→O.
-  ∀a:nat→O.∀p:is_increasing ? a.
-   is_increasing ? (λi.f (a i)).
-
-record is_order_continuous
- (O:dedekind_sigma_complete_ordered_set) (f:O→O) : Prop
-≝
- { ioc_is_sequentially_monotone: is_sequentially_monotone ? f;
-   ioc_is_upper_bound_f_sup:
-    ∀a:bounded_above_sequence O.
-     is_upper_bound ? (λi.f (a i)) (f (sup ? a));
-   ioc_respects_sup:
-    ∀a:bounded_above_sequence O.
-     is_increasing ? a →
-      f (sup ? a) =
-       sup ? (mk_bounded_above_sequence ? (λi.f (a i))
-        (mk_is_bounded_above ? ? (f (sup ? a))
-         (ioc_is_upper_bound_f_sup a)));
-   ioc_is_lower_bound_f_inf:
-    ∀a:bounded_below_sequence O.
-     is_lower_bound ? (λi.f (a i)) (f (inf ? a));
-   ioc_respects_inf:
-    ∀a:bounded_below_sequence O.
-     is_decreasing ? a →
-      f (inf ? a) =
-       inf ? (mk_bounded_below_sequence ? (λi.f (a i))
-        (mk_is_bounded_below ? ? (f (inf ? a))
-         (ioc_is_lower_bound_f_inf a)))   
- }.
-
-theorem tail_inf_increasing:
- ∀O:dedekind_sigma_complete_ordered_set.
-  ∀a:bounded_below_sequence O.
-   let y ≝ λi.mk_bounded_below_sequence ? (λj.a (i+j)) ? in
-   let x ≝ λi.inf ? (y i) in
-    is_increasing ? x.
- [ apply (mk_is_bounded_below ? ? (ib_lower_bound ? a a));
-   simplify;
-   intro;
-   apply (ib_lower_bound_is_lower_bound ? a a)
- | intros;
-   unfold is_increasing;
-   intro;
-   unfold x in ⊢ (? ? ? %);
-   apply (inf_greatest_lower_bound ? ? ? (inf_is_inf ? (y (S n))));
-   change with (is_lower_bound ? (y (S n)) (inf ? (y n)));
-   unfold is_lower_bound;
-   intro;
-   generalize in match (inf_lower_bound ? ? ? (inf_is_inf ? (y n)) (S n1));
-   (*CSC: coercion per FunClass inserita a mano*)
-   suppose (inf ? (y n) ≤ bbs_seq ? (y n) (S n1)) (H);
-   cut (bbs_seq ? (y n) (S n1) = bbs_seq ? (y (S n)) n1);
-    [ rewrite < Hcut;
-      assumption
-    | unfold y;
-      simplify;
-      auto paramodulation library
-    ]
- ].
-qed.
-
-definition is_liminf:
- ∀O:dedekind_sigma_complete_ordered_set.
-  bounded_below_sequence O → O → Prop.
- intros;
- apply
-  (is_sup ? (λi.inf ? (mk_bounded_below_sequence ? (λj.b (i+j)) ?)) t);
- apply (mk_is_bounded_below ? ? (ib_lower_bound ? b b));
- simplify;
- intros;
- apply (ib_lower_bound_is_lower_bound ? b b).
-qed.  
-
-definition liminf:
- ∀O:dedekind_sigma_complete_ordered_set.
-  bounded_sequence O → O.
- intros;
- apply
-  (sup ?
-   (mk_bounded_above_sequence ?
-     (λi.inf ?
-       (mk_bounded_below_sequence ?
-         (λj.b (i+j)) ?)) ?));
-  [ apply (mk_is_bounded_below ? ? (ib_lower_bound ? b b));
-    simplify;
-    intros;
-    apply (ib_lower_bound_is_lower_bound ? b b)
-  | apply (mk_is_bounded_above ? ? (ib_upper_bound ? b b));
-    unfold is_upper_bound;
-    intro;
-    change with
-     (inf O
-  (mk_bounded_below_sequence O (\lambda j:nat.b (n+j))
-   (mk_is_bounded_below O (\lambda j:nat.b (n+j)) (ib_lower_bound O b b)
-    (\lambda j:nat.ib_lower_bound_is_lower_bound O b b (n+j))))
-\leq ib_upper_bound O b b);
-    apply (inf_respects_le O);
-    simplify;
-    intro;
-    apply (ib_upper_bound_is_upper_bound ? b b)
-  ].
-qed.
-
-definition reverse_ordered_set: ordered_set → ordered_set.
- intros;
- apply mk_ordered_set;
-  [2:apply (λx,y:o.y ≤ x)
-  | skip
-  | apply mk_is_order_relation;
-     [ simplify;
-       intros;
-       apply (or_reflexive ? ? o)
-     | simplify;
-       intros;
-       apply (or_transitive ? ? o);
-        [2: apply H1
-        | skip
-        | assumption
-        ] 
-     | simplify;
-       intros;
-       apply (or_antisimmetric ? ? o);
-       assumption
-     ]
-  ].
-qed.
+definition reverse_pordered_set: pordered_set → pordered_set.
+intros (p); apply (mk_pordered_set (reverse_excedence p));
+generalize in match (reverse_excedence p); intros (E);
+apply mk_is_porder_relation;
+[apply le_reflexive|apply le_transitive|apply le_antisymmetric]
+qed. 
  
-interpretation "Ordered set ge" 'geq a b =
- (cic:/matita/ordered_sets/os_le.con _
-  (cic:/matita/ordered_sets/os_pre_ordered_set.con _
-   (cic:/matita/ordered_sets/reverse_ordered_set.con _ _)) a b).
-
 lemma is_lower_bound_reverse_is_upper_bound:
- ∀O:ordered_set.∀a:nat→O.∀l:O.
-  is_lower_bound O a l → is_upper_bound (reverse_ordered_set O) a l.
- intros;
- unfold;
- intro;
- unfold;
- unfold reverse_ordered_set;
- simplify;
- apply H.
+ ∀O:pordered_set.∀a:nat→O.∀l:O.
+  is_lower_bound O a l → is_upper_bound (reverse_pordered_set O) a l.
+intros (O a l H); unfold; intros (n); unfold reverse_pordered_set;
+unfold reverse_excedence; simplify; fold unfold le (le ? l (a n)); apply H;    
 qed.
 
 lemma is_upper_bound_reverse_is_lower_bound:
- ∀O:ordered_set.∀a:nat→O.∀l:O.
-  is_upper_bound O a l → is_lower_bound (reverse_ordered_set O) a l.
- intros;
- unfold;
- intro;
- unfold;
- unfold reverse_ordered_set;
- simplify;
- apply H.
+ ∀O:pordered_set.∀a:nat→O.∀l:O.
+  is_upper_bound O a l → is_lower_bound (reverse_pordered_set O) a l.
+intros (O a l H); unfold; intros (n); unfold reverse_pordered_set;
+unfold reverse_excedence; simplify; fold unfold le (le ? (a n) l); apply H;    
 qed.
 
 lemma reverse_is_lower_bound_is_upper_bound:
- ∀O:ordered_set.∀a:nat→O.∀l:O.
-  is_lower_bound (reverse_ordered_set O) a l → is_upper_bound O a l.
- intros;
- unfold in H;
- unfold reverse_ordered_set in H;
- apply H.
+ ∀O:pordered_set.∀a:nat→O.∀l:O.
+  is_lower_bound (reverse_pordered_set O) a l → is_upper_bound O a l.
+intros (O a l H); unfold; intros (n); unfold reverse_pordered_set in H;
+unfold reverse_excedence in H; simplify in H; apply H;    
 qed.
 
 lemma reverse_is_upper_bound_is_lower_bound:
- ∀O:ordered_set.∀a:nat→O.∀l:O.
-  is_upper_bound (reverse_ordered_set O) a l → is_lower_bound O a l.
- intros;
- unfold in H;
- unfold reverse_ordered_set in H;
- apply H.
+ ∀O:pordered_set.∀a:nat→O.∀l:O.
+  is_upper_bound (reverse_pordered_set O) a l → is_lower_bound O a l.
+intros (O a l H); unfold; intros (n); unfold reverse_pordered_set in H;
+unfold reverse_excedence in H; simplify in H; apply H;    
 qed.
 
-
 lemma is_inf_to_reverse_is_sup:
- ∀O:ordered_set.∀a:bounded_below_sequence O.∀l:O.
-  is_inf O a l → is_sup (reverse_ordered_set O) a l.
- intros;
- apply (mk_is_sup (reverse_ordered_set O));
-  [ apply is_lower_bound_reverse_is_upper_bound;
-    apply inf_lower_bound;
-    assumption
-  | intros;
-    change in v with (os_carrier O);
-    change with (v ≤ l);
-    apply (inf_greatest_lower_bound ? ? ? H);
-    apply reverse_is_upper_bound_is_lower_bound;
-    assumption
-  ].
+ ∀O:pordered_set.∀a:bounded_below_sequence O.∀l:O.
+  is_inf O a l → is_sup (reverse_pordered_set O) a l.
+intros (O a l H); apply (mk_is_sup (reverse_pordered_set O));
+[1: apply is_lower_bound_reverse_is_upper_bound; apply inf_lower_bound; assumption
+|2: unfold reverse_pordered_set; simplify; unfold reverse_excedence; simplify; 
+    intros (m H1); apply (inf_greatest_lower_bound ? ? ? H); apply H1;]
 qed.
- 
+
 lemma is_sup_to_reverse_is_inf:
- ∀O:ordered_set.∀a:bounded_above_sequence O.∀l:O.
-  is_sup O a l → is_inf (reverse_ordered_set O) a l.
- intros;
- apply (mk_is_inf (reverse_ordered_set O));
-  [ apply is_upper_bound_reverse_is_lower_bound;
-    apply sup_upper_bound;
-    assumption
-  | intros;
-    change in v with (os_carrier O);
-    change with (l ≤ v);
-    apply (sup_least_upper_bound ? ? ? H);
-    apply reverse_is_lower_bound_is_upper_bound;
-    assumption
-  ].
+ ∀O:pordered_set.∀a:bounded_above_sequence O.∀l:O.
+  is_sup O a l → is_inf (reverse_pordered_set O) a l.
+intros (O a l H); apply (mk_is_inf (reverse_pordered_set O));
+[1: apply is_upper_bound_reverse_is_lower_bound; apply sup_upper_bound; assumption
+|2: unfold reverse_pordered_set; simplify; unfold reverse_excedence; simplify; 
+    intros (m H1); apply (sup_least_upper_bound ? ? ? H); apply H1;]
 qed.
 
 lemma reverse_is_sup_to_is_inf:
- ∀O:ordered_set.∀a:bounded_above_sequence O.∀l:O.
-  is_sup (reverse_ordered_set O) a l → is_inf O a l.
- intros;
- apply mk_is_inf;
-  [ apply reverse_is_upper_bound_is_lower_bound;
-    change in l with (os_carrier (reverse_ordered_set O));
-    apply sup_upper_bound;
-    assumption
-  | intros;
-    change in l with (os_carrier (reverse_ordered_set O));
-    change in v with (os_carrier (reverse_ordered_set O));
-    change with (os_le (reverse_ordered_set O) l v);
-    apply (sup_least_upper_bound ? ? ? H);
-    change in v with (os_carrier O);
-    apply is_lower_bound_reverse_is_upper_bound;
-    assumption
-  ].
+ ∀O:pordered_set.∀a:bounded_above_sequence O.∀l:O.
+  is_sup (reverse_pordered_set O) a l → is_inf O a l.
+intros (O a l H); apply mk_is_inf;
+[1: apply reverse_is_upper_bound_is_lower_bound; 
+    apply (sup_upper_bound (reverse_pordered_set O)); assumption
+|2: intros (v H1); apply (sup_least_upper_bound (reverse_pordered_set O) a l H v);
+    apply is_lower_bound_reverse_is_upper_bound; assumption;]
 qed.
 
 lemma reverse_is_inf_to_is_sup:
- ∀O:ordered_set.∀a:bounded_above_sequence O.∀l:O.
-  is_inf (reverse_ordered_set O) a l → is_sup O a l.
- intros;
- apply mk_is_sup;
-  [ apply reverse_is_lower_bound_is_upper_bound;
-    change in l with (os_carrier (reverse_ordered_set O));
-    apply (inf_lower_bound ? ? ? H)
-  | intros;
-    change in l with (os_carrier (reverse_ordered_set O));
-    change in v with (os_carrier (reverse_ordered_set O));
-    change with (os_le (reverse_ordered_set O) v l);
-    apply (inf_greatest_lower_bound ? ? ? H);
-    change in v with (os_carrier O);
-    apply is_upper_bound_reverse_is_lower_bound;
-    assumption
-  ].
-qed.
-
-
-definition reverse_dedekind_sigma_complete_ordered_set:
- dedekind_sigma_complete_ordered_set → dedekind_sigma_complete_ordered_set.
- intros;
- apply mk_dedekind_sigma_complete_ordered_set;
-  [ apply (reverse_ordered_set d)
-  | elim daemon
-    (*apply mk_is_dedekind_sigma_complete;
-     [ intros;
-       elim (dsc_sup ? ? d a m) 0;
-        [ generalize in match H; clear H;
-          generalize in match m; clear m;
-          elim d;
-          simplify in a1;
-          simplify;
-          change in a1 with (Type_OF_ordered_set ? (reverse_ordered_set ? o)); 
-          apply (ex_intro ? ? a1);
-          simplify in H1;
-          change in m with (Type_OF_ordered_set ? o);
-          apply (is_sup_to_reverse_is_inf ? ? ? ? H1)
-        | generalize in match H; clear H;
-          generalize in match m; clear m;
-          elim d;
-          simplify;
-          change in t with (Type_OF_ordered_set ? o);
-          simplify in t;
-          apply reverse_is_lower_bound_is_upper_bound;
-          assumption
-        ]
-     | apply is_sup_reverse_is_inf;
-     | apply m
-     | 
-     ]*)
-  ].
-qed.
-
-definition reverse_bounded_sequence:
- ∀O:dedekind_sigma_complete_ordered_set.
-  bounded_sequence O →
-   bounded_sequence (reverse_dedekind_sigma_complete_ordered_set O).
- intros;
- apply mk_bounded_sequence;
-  [ apply bs_seq;
-    unfold reverse_dedekind_sigma_complete_ordered_set;
-    simplify;
-    elim daemon
-  | elim daemon
-  | elim daemon
-  ].
-qed.
-
-definition limsup ≝
- λO:dedekind_sigma_complete_ordered_set.
-  λa:bounded_sequence O.
-   liminf (reverse_dedekind_sigma_complete_ordered_set O)
-    (reverse_bounded_sequence O a).
-
-notation "hvbox(〈a〉)"
- non associative with precedence 45
-for @{ 'hide_everything_but $a }.
-
-interpretation "mk_bounded_above_sequence" 'hide_everything_but a
-= (cic:/matita/ordered_sets/bounded_above_sequence.ind#xpointer(1/1/1) _ _ a _).
-
-interpretation "mk_bounded_below_sequence" 'hide_everything_but a
-= (cic:/matita/ordered_sets/bounded_below_sequence.ind#xpointer(1/1/1) _ _ a _).
-
-theorem eq_f_sup_sup_f:
- ∀O':dedekind_sigma_complete_ordered_set.
-  ∀f:O'→O'. ∀H:is_order_continuous ? f.
-   ∀a:bounded_above_sequence O'.
-    ∀p:is_increasing ? a.
-     f (sup ? a) = sup ? (mk_bounded_above_sequence ? (λi.f (a i)) ?).
- [ apply (mk_is_bounded_above ? ? (f (sup ? a))); 
-   apply ioc_is_upper_bound_f_sup;
-   assumption
- | intros;
-   apply ioc_respects_sup;
-   assumption
- ].
-qed.
-
-theorem eq_f_sup_sup_f':
- ∀O':dedekind_sigma_complete_ordered_set.
-  ∀f:O'→O'. ∀H:is_order_continuous ? f.
-   ∀a:bounded_above_sequence O'.
-    ∀p:is_increasing ? a.
-     ∀p':is_bounded_above ? (λi.f (a i)).
-      f (sup ? a) = sup ? (mk_bounded_above_sequence ? (λi.f (a i)) p').
- intros;
- rewrite > (eq_f_sup_sup_f ? f H a H1);
- apply sup_proof_irrelevant;
- reflexivity.
-qed.
-
-theorem eq_f_liminf_sup_f_inf:
- ∀O':dedekind_sigma_complete_ordered_set.
-  ∀f:O'→O'. ∀H:is_order_continuous ? f.
-   ∀a:bounded_sequence O'.
-   let p1 := ? in
-    f (liminf ? a) =
-     sup ?
-      (mk_bounded_above_sequence ?
-        (λi.f (inf ?
-          (mk_bounded_below_sequence ?
-            (λj.a (i+j))
-            ?)))
-        p1).
- [ apply (mk_is_bounded_below ? ? (ib_lower_bound ? a a));
-   simplify;
-   intro;
-   apply (ib_lower_bound_is_lower_bound ? a a)
- | apply (mk_is_bounded_above ? ? (f (sup ? a)));
-   unfold is_upper_bound;
-   intro;
-   apply (or_transitive ? ? O' ? (f (a n)));
-    [ generalize in match (ioc_is_lower_bound_f_inf ? ? H);
-      intro H1;
-      simplify in H1;
-      rewrite > (plus_n_O n) in ⊢ (? ? ? (? (? ? ? %)));
-      apply (H1 (mk_bounded_below_sequence O' (\lambda j:nat.a (n+j))
-(mk_is_bounded_below O' (\lambda j:nat.a (n+j)) (ib_lower_bound O' a a)
- (\lambda j:nat.ib_lower_bound_is_lower_bound O' a a (n+j)))) O);
-    | elim daemon (*apply (ioc_is_upper_bound_f_sup ? ? ? H)*)
-    ]
- | intros;
-   unfold liminf;
-   clearbody p1;
-   generalize in match (\lambda n:nat
-.inf_respects_le O'
- (mk_bounded_below_sequence O' (\lambda j:nat.a (plus n j))
-  (mk_is_bounded_below O' (\lambda j:nat.a (plus n j))
-   (ib_lower_bound O' a a)
-   (\lambda j:nat.ib_lower_bound_is_lower_bound O' a a (plus n j))))
- (ib_upper_bound O' a a)
- (\lambda n1:nat.ib_upper_bound_is_upper_bound O' a a (plus n n1)));
-   intro p2;
-   apply (eq_f_sup_sup_f' ? f H (mk_bounded_above_sequence O'
-(\lambda i:nat
- .inf O'
-  (mk_bounded_below_sequence O' (\lambda j:nat.a (plus i j))
-   (mk_is_bounded_below O' (\lambda j:nat.a (plus i j))
-    (ib_lower_bound O' a a)
-    (\lambda n:nat.ib_lower_bound_is_lower_bound O' a a (plus i n)))))
-(mk_is_bounded_above O'
- (\lambda i:nat
-  .inf O'
-   (mk_bounded_below_sequence O' (\lambda j:nat.a (plus i j))
-    (mk_is_bounded_below O' (\lambda j:nat.a (plus i j))
-     (ib_lower_bound O' a a)
-     (\lambda n:nat.ib_lower_bound_is_lower_bound O' a a (plus i n)))))
- (ib_upper_bound O' a a) p2)));
-   unfold bas_seq;
-   change with
-    (is_increasing ? (\lambda i:nat
-.inf O'
- (mk_bounded_below_sequence O' (\lambda j:nat.a (plus i j))
-  (mk_is_bounded_below O' (\lambda j:nat.a (plus i j))
-   (ib_lower_bound O' a a)
-   (\lambda n:nat.ib_lower_bound_is_lower_bound O' a a (plus i n))))));
-   apply tail_inf_increasing
- ].
-qed.
-
-
-
-
-definition lt ≝ λO:ordered_set.λa,b:O.a ≤ b ∧ a ≠ b.
-
-interpretation "Ordered set lt" 'lt a b =
- (cic:/matita/ordered_sets/lt.con _ a b).
+ ∀O:pordered_set.∀a:bounded_above_sequence O.∀l:O.
+  is_inf (reverse_pordered_set O) a l → is_sup O a l.
+intros (O a l H); apply mk_is_sup;
+[1: apply reverse_is_lower_bound_is_upper_bound; 
+    apply (inf_lower_bound (reverse_pordered_set O)); assumption
+|2: intros (v H1); apply (inf_greatest_lower_bound (reverse_pordered_set O) a l H v);
+    apply is_upper_bound_reverse_is_lower_bound; assumption;]
+qed.
+
+definition total_order_property : ∀E:excedence. Type ≝
+  λE:excedence. ∀a,b:E. a ≰ b → b < a.
+
+record tordered_set : Type ≝ {
+ tos_poset:> pordered_set;
+ tos_totality: total_order_property tos_poset
+}.