(* *)
(**************************************************************************)
-set "baseuri" "cic:/matita/nat/iteration2".
-
include "nat/primes.ma".
include "nat/ord.ma".
include "nat/generic_iter_p.ma".
include "nat/count.ma".(*necessary just to use bool_to_nat and bool_to_nat_andb*)
-
(* sigma_p on nautral numbers is a specialization of sigma_p_gen *)
definition sigma_p: nat \to (nat \to bool) \to (nat \to nat) \to nat \def
\lambda n, p, g. (iter_p_gen n p nat g O plus).
assumption.
qed.
+theorem or_false_to_eq_sigma_p:
+\forall n,m:nat.\forall p:nat \to bool.
+\forall g: nat \to nat.
+n \le m \to (\forall i:nat. n \le i \to i < m \to p i = false \lor g i = O)
+\to sigma_p m p g = sigma_p n p g.
+intros.
+unfold sigma_p.
+apply or_false_eq_baseA_to_eq_iter_p_gen
+ [intros.reflexivity
+ |assumption
+ |assumption
+ ]
+qed.
+
+theorem bool_to_nat_to_eq_sigma_p:
+\forall n:nat.\forall p1,p2:nat \to bool.
+\forall g1,g2: nat \to nat.
+(\forall i:nat.
+bool_to_nat (p1 i)*(g1 i) = bool_to_nat (p2 i)*(g2 i))
+\to sigma_p n p1 g1 = sigma_p n p2 g2.
+intros.elim n
+ [reflexivity
+ |generalize in match (H n1).
+ apply (bool_elim ? (p1 n1));intro
+ [apply (bool_elim ? (p2 n1));intros
+ [rewrite > true_to_sigma_p_Sn
+ [rewrite > true_to_sigma_p_Sn
+ [apply eq_f2
+ [simplify in H4.
+ rewrite > plus_n_O.
+ rewrite > plus_n_O in ⊢ (? ? ? %).
+ assumption
+ |assumption
+ ]
+ |assumption
+ ]
+ |assumption
+ ]
+ |rewrite > true_to_sigma_p_Sn
+ [rewrite > false_to_sigma_p_Sn
+ [change in ⊢ (? ? ? %) with (O + sigma_p n1 p2 g2).
+ apply eq_f2
+ [simplify in H4.
+ rewrite > plus_n_O.
+ assumption
+ |assumption
+ ]
+ |assumption
+ ]
+ |assumption
+ ]
+ ]
+ |apply (bool_elim ? (p2 n1));intros
+ [rewrite > false_to_sigma_p_Sn
+ [rewrite > true_to_sigma_p_Sn
+ [change in ⊢ (? ? % ?) with (O + sigma_p n1 p1 g1).
+ apply eq_f2
+ [simplify in H4.
+ rewrite < plus_n_O in H4.
+ assumption
+ |assumption
+ ]
+ |assumption
+ ]
+ |assumption
+ ]
+ |rewrite > false_to_sigma_p_Sn
+ [rewrite > false_to_sigma_p_Sn
+ [assumption
+ |assumption
+ ]
+ |assumption
+ ]
+ ]
+ ]
+ ]
+qed.
+
theorem sigma_p2 :
\forall n,m:nat.
\forall p1,p2:nat \to bool.
]
qed.
+theorem eq_sigma_p_pred:
+\forall n,p,g. p O = true \to
+sigma_p (S n) (\lambda i.p (pred i)) (\lambda i.g(pred i)) =
+plus (sigma_p n p g) (g O).
+intros.
+unfold sigma_p.
+apply eq_iter_p_gen_pred
+ [assumption
+ |apply symmetricIntPlus
+ |apply associative_plus
+ |intros.apply sym_eq.apply plus_n_O
+ ]
+qed.
+
(* monotonicity *)
theorem le_sigma_p:
\forall n:nat. \forall p:nat \to bool. \forall g1,g2:nat \to nat.
]
qed.
+(* a slightly more general result *)
+theorem le_sigma_p1:
+\forall n:nat. \forall p1,p2:nat \to bool. \forall g1,g2:nat \to nat.
+(\forall i. i < n \to
+bool_to_nat (p1 i)*(g1 i) \le bool_to_nat (p2 i)*g2 i) \to
+sigma_p n p1 g1 \le sigma_p n p2 g2.
+intros.
+generalize in match H.
+elim n
+ [apply le_n.
+ |apply (bool_elim ? (p1 n1));intros
+ [apply (bool_elim ? (p2 n1));intros
+ [rewrite > true_to_sigma_p_Sn
+ [rewrite > true_to_sigma_p_Sn in ⊢ (? ? %)
+ [apply le_plus
+ [lapply (H2 n1) as H5
+ [rewrite > H3 in H5.
+ rewrite > H4 in H5.
+ simplify in H5.
+ rewrite < plus_n_O in H5.
+ rewrite < plus_n_O in H5.
+ assumption
+ |apply le_S_S.apply le_n
+ ]
+ |apply H1.intros.
+ apply H2.apply le_S.assumption
+ ]
+ |assumption
+ ]
+ |assumption
+ ]
+ |rewrite > true_to_sigma_p_Sn
+ [rewrite > false_to_sigma_p_Sn in ⊢ (? ? %)
+ [change in ⊢ (? ? %) with (O + sigma_p n1 p2 g2).
+ apply le_plus
+ [lapply (H2 n1) as H5
+ [rewrite > H3 in H5.
+ rewrite > H4 in H5.
+ simplify in H5.
+ rewrite < plus_n_O in H5.
+ assumption
+ |apply le_S_S.apply le_n
+ ]
+ |apply H1.intros.
+ apply H2.apply le_S.assumption
+ ]
+ |assumption
+ ]
+ |assumption
+ ]
+ ]
+ |apply (bool_elim ? (p2 n1));intros
+ [rewrite > false_to_sigma_p_Sn
+ [rewrite > true_to_sigma_p_Sn in ⊢ (? ? %)
+ [change in ⊢ (? % ?) with (O + sigma_p n1 p1 g1).
+ apply le_plus
+ [lapply (H2 n1) as H5
+ [rewrite > H3 in H5.
+ rewrite > H4 in H5.
+ simplify in H5.
+ rewrite < plus_n_O in H5.
+ assumption
+ |apply le_S_S.apply le_n
+ ]
+ |apply H1.intros.
+ apply H2.apply le_S.assumption
+ ]
+ |assumption
+ ]
+ |assumption
+ ]
+ |rewrite > false_to_sigma_p_Sn
+ [rewrite > false_to_sigma_p_Sn in ⊢ (? ? %)
+ [apply H1.intros.
+ apply H2.apply le_S.assumption
+ |assumption
+ ]
+ |assumption
+ ]
+ ]
+ ]
+ ]
+qed.
+
theorem lt_sigma_p:
\forall n:nat. \forall p:nat \to bool. \forall g1,g2:nat \to nat.
(\forall i. i < n \to p i = true \to g1 i \le g2 i ) \to
qed.
theorem sigma_p_plus_1: \forall n:nat. \forall f,g:nat \to nat.
-sigma_p n (\lambda b:nat. true) (\lambda a:nat.(f a) + (g a)) =
-sigma_p n (\lambda b:nat. true) f + sigma_p n (\lambda b:nat. true) g.
+\forall p.
+sigma_p n p (\lambda a:nat.(f a) + (g a)) =
+sigma_p n p f + sigma_p n p g.
intros.
elim n
[ simplify.
reflexivity
-| rewrite > true_to_sigma_p_Sn
- [ rewrite > (true_to_sigma_p_Sn n1 (\lambda c:nat.true) f)
- [ rewrite > (true_to_sigma_p_Sn n1 (\lambda c:nat.true) g)
- [ rewrite > assoc_plus in \vdash (? ? ? %).
- rewrite < assoc_plus in \vdash (? ? ? (? ? %)).
- rewrite < sym_plus in \vdash (? ? ? (? ? (? % ?))).
- rewrite > assoc_plus in \vdash (? ? ? (? ? %)).
- rewrite < assoc_plus in \vdash (? ? ? %).
- apply eq_f.
- assumption
- | reflexivity
- ]
- | reflexivity
- ]
- | reflexivity
- ]
-]
+| apply (bool_elim ? (p n1)); intro;
+ [ rewrite > true_to_sigma_p_Sn
+ [ rewrite > (true_to_sigma_p_Sn n1 p f)
+ [ rewrite > (true_to_sigma_p_Sn n1 p g)
+ [ rewrite > assoc_plus in \vdash (? ? ? %).
+ rewrite < assoc_plus in \vdash (? ? ? (? ? %)).
+ rewrite < sym_plus in \vdash (? ? ? (? ? (? % ?))).
+ rewrite > assoc_plus in \vdash (? ? ? (? ? %)).
+ rewrite < assoc_plus in \vdash (? ? ? %).
+ apply eq_f.
+ assumption]]]
+ assumption
+ | rewrite > false_to_sigma_p_Sn
+ [ rewrite > (false_to_sigma_p_Sn n1 p f)
+ [ rewrite > (false_to_sigma_p_Sn n1 p g)
+ [assumption]]]
+ assumption
+]]
qed.
-
theorem eq_sigma_p_sigma_p_times1 : \forall n,m:nat.\forall f:nat \to nat.
sigma_p (n*m) (\lambda x:nat.true) f =
sigma_p m (\lambda x:nat.true)
apply eq_sigma_p_sigma_p_times1.
qed.
-
theorem sigma_p_times:\forall n,m:nat.
\forall f,f1,f2:nat \to bool.
\forall g:nat \to nat \to nat.
| assumption
| assumption
]
+qed.
+
+theorem sigma_p_sigma_p:
+\forall g: nat \to nat \to nat.
+\forall n,m.
+\forall p11,p21:nat \to bool.
+\forall p12,p22:nat \to nat \to bool.
+(\forall x,y. x < n \to y < m \to
+ (p11 x \land p12 x y) = (p21 y \land p22 y x)) \to
+sigma_p n p11 (\lambda x:nat.sigma_p m (p12 x) (\lambda y. g x y)) =
+sigma_p m p21 (\lambda y:nat.sigma_p n (p22 y) (\lambda x. g x y)).
+intros.
+unfold sigma_p.unfold sigma_p.
+apply (iter_p_gen_iter_p_gen ? ? ? sym_plus assoc_plus)
+ [intros.apply sym_eq.apply plus_n_O.
+ |assumption
+ ]
qed.
\ No newline at end of file