1 (**************************************************************************)
4 (* ||A|| A project by Andrea Asperti *)
6 (* ||I|| Developers: *)
7 (* ||T|| The HELM team. *)
8 (* ||A|| http://helm.cs.unibo.it *)
10 (* \ / This file is distributed under the terms of the *)
11 (* v GNU General Public License Version 2 *)
13 (**************************************************************************)
15 set "baseuri" "cic:/matita/sequence/".
17 include "ordered_set.ma".
19 definition is_increasing ≝ λO:pordered_set.λa:nat→O.∀n:nat.a n ≤ a (S n).
20 definition is_decreasing ≝ λO:pordered_set.λa:nat→O.∀n:nat.a (S n) ≤ a n.
22 definition is_upper_bound ≝ λO:pordered_set.λa:nat→O.λu:O.∀n:nat.a n ≤ u.
23 definition is_lower_bound ≝ λO:pordered_set.λa:nat→O.λu:O.∀n:nat.u ≤ a n.
25 record is_sup (O:pordered_set) (a:nat→O) (u:O) : Prop ≝
26 { sup_upper_bound: is_upper_bound O a u;
27 sup_least_upper_bound: ∀v:O. is_upper_bound O a v → u≤v
30 record is_inf (O:pordered_set) (a:nat→O) (u:O) : Prop ≝
31 { inf_lower_bound: is_lower_bound O a u;
32 inf_greatest_lower_bound: ∀v:O. is_lower_bound O a v → v≤u
35 record is_bounded_below (O:pordered_set) (a:nat→O) : Type ≝
37 ib_lower_bound_is_lower_bound: is_lower_bound ? a ib_lower_bound
40 record is_bounded_above (O:pordered_set) (a:nat→O) : Type ≝
42 ib_upper_bound_is_upper_bound: is_upper_bound ? a ib_upper_bound
45 record is_bounded (O:pordered_set) (a:nat→O) : Type ≝
46 { ib_bounded_below:> is_bounded_below ? a;
47 ib_bounded_above:> is_bounded_above ? a
50 record bounded_below_sequence (O:pordered_set) : Type ≝
52 bbs_is_bounded_below:> is_bounded_below ? bbs_seq
55 record bounded_above_sequence (O:pordered_set) : Type ≝
57 bas_is_bounded_above:> is_bounded_above ? bas_seq
60 record bounded_sequence (O:pordered_set) : Type ≝
62 bs_is_bounded_below: is_bounded_below ? bs_seq;
63 bs_is_bounded_above: is_bounded_above ? bs_seq
66 definition bounded_below_sequence_of_bounded_sequence ≝
67 λO:pordered_set.λb:bounded_sequence O.
68 mk_bounded_below_sequence ? b (bs_is_bounded_below ? b).
70 coercion cic:/matita/sequence/bounded_below_sequence_of_bounded_sequence.con.
72 definition bounded_above_sequence_of_bounded_sequence ≝
73 λO:pordered_set.λb:bounded_sequence O.
74 mk_bounded_above_sequence ? b (bs_is_bounded_above ? b).
76 coercion cic:/matita/sequence/bounded_above_sequence_of_bounded_sequence.con.
78 definition lower_bound ≝
79 λO:pordered_set.λb:bounded_below_sequence O.
80 ib_lower_bound ? b (bbs_is_bounded_below ? b).
82 lemma lower_bound_is_lower_bound:
83 ∀O:pordered_set.∀b:bounded_below_sequence O.
84 is_lower_bound ? b (lower_bound ? b).
85 intros; unfold lower_bound; apply ib_lower_bound_is_lower_bound.
88 definition upper_bound ≝
89 λO:pordered_set.λb:bounded_above_sequence O.
90 ib_upper_bound ? b (bas_is_bounded_above ? b).
92 lemma upper_bound_is_upper_bound:
93 ∀O:pordered_set.∀b:bounded_above_sequence O.
94 is_upper_bound ? b (upper_bound ? b).
95 intros; unfold upper_bound; apply ib_upper_bound_is_upper_bound.
98 definition reverse_excedence: excedence → excedence.
99 intros (E); apply (mk_excedence E); [apply (λx,y.exc_relation E y x)]
100 cases E (T f cRf cTf); simplify;
101 [1: unfold Not; intros (x H); apply (cRf x); assumption
102 |2: intros (x y z); apply Or_symmetric; apply cTf; assumption;]
105 definition reverse_pordered_set: pordered_set → pordered_set.
106 intros (p); apply (mk_pordered_set (reverse_excedence p));
107 generalize in match (reverse_excedence p); intros (E);
108 apply mk_is_porder_relation;
109 [apply le_reflexive|apply le_transitive|apply le_antisymmetric]
112 lemma is_lower_bound_reverse_is_upper_bound:
113 ∀O:pordered_set.∀a:nat→O.∀l:O.
114 is_lower_bound O a l → is_upper_bound (reverse_pordered_set O) a l.
115 intros (O a l H); unfold; intros (n); unfold reverse_pordered_set;
116 unfold reverse_excedence; simplify; fold unfold le (le ? l (a n)); apply H;
119 lemma is_upper_bound_reverse_is_lower_bound:
120 ∀O:pordered_set.∀a:nat→O.∀l:O.
121 is_upper_bound O a l → is_lower_bound (reverse_pordered_set O) a l.
122 intros (O a l H); unfold; intros (n); unfold reverse_pordered_set;
123 unfold reverse_excedence; simplify; fold unfold le (le ? (a n) l); apply H;
126 lemma reverse_is_lower_bound_is_upper_bound:
127 ∀O:pordered_set.∀a:nat→O.∀l:O.
128 is_lower_bound (reverse_pordered_set O) a l → is_upper_bound O a l.
129 intros (O a l H); unfold; intros (n); unfold reverse_pordered_set in H;
130 unfold reverse_excedence in H; simplify in H; apply H;
133 lemma reverse_is_upper_bound_is_lower_bound:
134 ∀O:pordered_set.∀a:nat→O.∀l:O.
135 is_upper_bound (reverse_pordered_set O) a l → is_lower_bound O a l.
136 intros (O a l H); unfold; intros (n); unfold reverse_pordered_set in H;
137 unfold reverse_excedence in H; simplify in H; apply H;
140 lemma is_inf_to_reverse_is_sup:
141 ∀O:pordered_set.∀a:bounded_below_sequence O.∀l:O.
142 is_inf O a l → is_sup (reverse_pordered_set O) a l.
143 intros (O a l H); apply (mk_is_sup (reverse_pordered_set O));
144 [1: apply is_lower_bound_reverse_is_upper_bound; apply inf_lower_bound; assumption
145 |2: unfold reverse_pordered_set; simplify; unfold reverse_excedence; simplify;
146 intros (m H1); apply (inf_greatest_lower_bound ? ? ? H); apply H1;]
149 lemma is_sup_to_reverse_is_inf:
150 ∀O:pordered_set.∀a:bounded_above_sequence O.∀l:O.
151 is_sup O a l → is_inf (reverse_pordered_set O) a l.
152 intros (O a l H); apply (mk_is_inf (reverse_pordered_set O));
153 [1: apply is_upper_bound_reverse_is_lower_bound; apply sup_upper_bound; assumption
154 |2: unfold reverse_pordered_set; simplify; unfold reverse_excedence; simplify;
155 intros (m H1); apply (sup_least_upper_bound ? ? ? H); apply H1;]
158 lemma reverse_is_sup_to_is_inf:
159 ∀O:pordered_set.∀a:bounded_above_sequence O.∀l:O.
160 is_sup (reverse_pordered_set O) a l → is_inf O a l.
161 intros (O a l H); apply mk_is_inf;
162 [1: apply reverse_is_upper_bound_is_lower_bound;
163 apply (sup_upper_bound (reverse_pordered_set O)); assumption
164 |2: intros (v H1); apply (sup_least_upper_bound (reverse_pordered_set O) a l H v);
165 apply is_lower_bound_reverse_is_upper_bound; assumption;]
168 lemma reverse_is_inf_to_is_sup:
169 ∀O:pordered_set.∀a:bounded_above_sequence O.∀l:O.
170 is_inf (reverse_pordered_set O) a l → is_sup O a l.
171 intros (O a l H); apply mk_is_sup;
172 [1: apply reverse_is_lower_bound_is_upper_bound;
173 apply (inf_lower_bound (reverse_pordered_set O)); assumption
174 |2: intros (v H1); apply (inf_greatest_lower_bound (reverse_pordered_set O) a l H v);
175 apply is_upper_bound_reverse_is_lower_bound; assumption;]