-include "sequence.ma".
-include "nat/plus.ma".
-
-definition d2s ≝
- λR.λml:mlattice R.λs:sequence (pordered_set_of_excedence ml).λk.λn. δ (s n) k.
-(*
-notation "s ⇝ 'Zero'" non associative with precedence 50 for @{'tends0 $s }.
-
-interpretation "tends to" 'tends s x =
- (cic:/matita/sequence/tends0.con _ s).
-*)
-
-lemma lew_opp : ∀O:ogroup.∀a,b,c:O.0 ≤ b → a ≤ c → a + -b ≤ c.
-intros (O a b c L0 L);
-apply (le_transitive ????? L);
-apply (plus_cancl_le ??? (-a));
-apply (le_rewr ??? 0 (opp_inverse ??));
-apply (le_rewl ??? (-a+a+-b) (plus_assoc ????));
-apply (le_rewl ??? (0+-b) (opp_inverse ??));
-apply (le_rewl ??? (-b) (zero_neutral ?(-b)));
-apply le_zero_x_to_le_opp_x_zero;
-assumption;
-qed.
-
-
-lemma ltw_opp : ∀O:ogroup.∀a,b,c:O.0 < b → a < c → a + -b < c.
-intros (O a b c P L);
-apply (lt_transitive ????? L);
-apply (plus_cancl_lt ??? (-a));
-apply (lt_rewr ??? 0 (opp_inverse ??));
-apply (lt_rewl ??? (-a+a+-b) (plus_assoc ????));
-apply (lt_rewl ??? (0+-b) (opp_inverse ??));
-apply (lt_rewl ??? ? (zero_neutral ??));
-apply lt_zero_x_to_lt_opp_x_zero;
-assumption;
-qed.
-
-lemma ltwl: ∀a,b,c:nat. b + a < c → a < c.
-intros 3 (x y z); elim y (H z IH H); [apply H]
-apply IH; apply lt_S_to_lt; apply H;
-qed.
-
-lemma ltwr: ∀a,b,c:nat. a + b < c → a < c.
-intros 3 (x y z); rewrite > sym_plus; apply ltwl;
-qed.
-
-alias symbol "leq" = "ordered sets less or equal than".
-alias symbol "and" = "constructive and".
-alias symbol "exists" = "constructive exists (Type)".
-theorem carabinieri: (* non trova la coercion .... *)
- ∀R.∀ml:mlattice R.∀an,bn,xn:sequence (pordered_set_of_excedence ml).
- (∀n. (an n ≤ xn n) ∧ (xn n ≤ bn n)) →
- ∀x:ml. tends0 ? (d2s ? ml an x) → tends0 ? (d2s ? ml bn x) →
- tends0 ? (d2s ? ml xn x).
-intros (R ml an bn xn H x Ha Hb); unfold tends0 in Ha Hb ⊢ %. unfold d2s in Ha Hb ⊢ %.
-intros (e He);
-elim (Ha ? He) (n1 H1); clear Ha; elim (Hb e He) (n2 H2); clear Hb;
-constructor 1; [apply (n1 + n2);] intros (n3 Hn3);
-lapply (ltwr ??? Hn3) as Hn1n3; lapply (ltwl ??? Hn3) as Hn2n3;
-elim (H1 ? Hn1n3) (H3 H4); elim (H2 ? Hn2n3) (H5 H6); clear Hn1n3 Hn2n3;
-elim (H n3) (H7 H8); clear H H1 H2;
-lapply (le_to_eqm ??? H7) as Dxm; lapply (le_to_eqj ??? H7) as Dym;
-(* the main step *)
-cut (δ (xn n3) x ≤ δ (bn n3) x + δ (an n3) x + δ (an n3) x); [2:
- apply (le_transitive ???? (mtineq ???? (an n3)));
- lapply (le_mtri ????? H7 H8);
- lapply (feq_plusr ? (- δ(xn n3) (bn n3)) ?? Hletin);
- cut ( δ(an n3) (bn n3)+- δ(xn n3) (bn n3)≈( δ(an n3) (xn n3))); [2:
- apply (Eq≈ (0 + δ(an n3) (xn n3)) ? (zero_neutral ??));
- apply (Eq≈ (δ(an n3) (xn n3) + 0) ? (plus_comm ???));
- apply (Eq≈ (δ(an n3) (xn n3) + (-δ(xn n3) (bn n3) + δ(xn n3) (bn n3))) ? (opp_inverse ??));
- apply (Eq≈ (δ(an n3) (xn n3) + (δ(xn n3) (bn n3) + -δ(xn n3) (bn n3))) ? (plus_comm ?? (δ(xn n3) (bn n3))));
- apply (Eq≈ ? ? (eq_sym ??? (plus_assoc ????))); assumption;] clear Hletin1;
- apply (le_rewl ??? ( δ(an n3) (xn n3)+ δ(an n3) x));[
- apply feq_plusr; apply msymmetric;]
- apply (le_rewl ??? (δ(an n3) (bn n3)+- δ(xn n3) (bn n3)+ δ(an n3) x));[
- apply feq_plusr; assumption;]
- clear Hcut Hletin Dym Dxm H8 H7 H6 H5 H4 H3;
- apply (le_rewl ??? (- δ(xn n3) (bn n3)+ δ(an n3) (bn n3)+δ(an n3) x));[
- apply feq_plusr; apply plus_comm;]
- apply (le_rewl ??? (- δ(xn n3) (bn n3)+ (δ(an n3) (bn n3)+δ(an n3) x)) (plus_assoc ????));
- apply (le_rewl ??? ((δ(an n3) (bn n3)+δ(an n3) x)+- δ(xn n3) (bn n3)) (plus_comm ???));
- apply lew_opp; [apply mpositive] apply fle_plusr;
- apply (le_rewr ???? (plus_comm ???));
- apply (le_rewr ??? ( δ(an n3) x+ δx (bn n3)) (msymmetric ????));
- apply mtineq;]
-split; [
- apply (lt_le_transitive ????? (mpositive ????));
- split; elim He; [apply le_zero_x_to_le_opp_x_zero; assumption;]
- cases t1; [
- left; apply exc_zero_opp_x_to_exc_x_zero;
- apply (Ex≫ ? (eq_opp_opp_x_x ??));assumption;]
- right; apply exc_opp_x_zero_to_exc_zero_x;
- apply (Ex≪ ? (eq_opp_opp_x_x ??)); assumption;]
-clear Dxm Dym H7 H8 Hn3 H5 H3 n1 n2;