src/HOL/List.ML
author oheimb
Mon Sep 21 23:03:11 1998 +0200 (1998-09-21)
changeset 5518 654ead0ba4f7
parent 5448 40a09282ba14
child 5537 c2bd39a2c0ee
permissions -rw-r--r--
re-added mem and list_all
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(*  Title:      HOL/List
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    ID:         $Id$
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    Author:     Tobias Nipkow
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    Copyright   1994 TU Muenchen
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List lemmas
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*)
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Goal "!x. xs ~= x#xs";
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by (induct_tac "xs" 1);
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by Auto_tac;
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qed_spec_mp "not_Cons_self";
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bind_thm("not_Cons_self2",not_Cons_self RS not_sym);
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Addsimps [not_Cons_self,not_Cons_self2];
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Goal "(xs ~= []) = (? y ys. xs = y#ys)";
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by (induct_tac "xs" 1);
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by Auto_tac;
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qed "neq_Nil_conv";
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(* Induction over the length of a list: *)
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val [prem] = Goal
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  "(!!xs. (!ys. length ys < length xs --> P ys) ==> P xs) ==> P(xs)";
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by (rtac measure_induct 1 THEN etac prem 1);
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qed "length_induct";
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(** "lists": the list-forming operator over sets **)
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Goalw lists.defs "A<=B ==> lists A <= lists B";
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by (rtac lfp_mono 1);
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by (REPEAT (ares_tac basic_monos 1));
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qed "lists_mono";
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val listsE = lists.mk_cases list.simps  "x#l : lists A";
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AddSEs [listsE];
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AddSIs lists.intrs;
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Goal "l: lists A ==> l: lists B --> l: lists (A Int B)";
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by (etac lists.induct 1);
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by (ALLGOALS Blast_tac);
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qed_spec_mp "lists_IntI";
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Goal "lists (A Int B) = lists A Int lists B";
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by (rtac (mono_Int RS equalityI) 1);
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by (simp_tac (simpset() addsimps [mono_def, lists_mono]) 1);
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by (blast_tac (claset() addSIs [lists_IntI]) 1);
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qed "lists_Int_eq";
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Addsimps [lists_Int_eq];
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(**  Case analysis **)
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section "Case analysis";
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val prems = Goal "[| P([]); !!x xs. P(x#xs) |] ==> P(xs)";
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by (induct_tac "xs" 1);
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by (REPEAT(resolve_tac prems 1));
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qed "list_cases";
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Goal "(xs=[] --> P([])) & (!y ys. xs=y#ys --> P(y#ys)) --> P(xs)";
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by (induct_tac "xs" 1);
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by (Blast_tac 1);
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by (Blast_tac 1);
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bind_thm("list_eq_cases",
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  impI RSN (2,allI RSN (2,allI RSN (2,impI RS (conjI RS (result() RS mp))))));
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(** length **)
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(* needs to come before "@" because of thm append_eq_append_conv *)
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section "length";
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Goal "length(xs@ys) = length(xs)+length(ys)";
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by (induct_tac "xs" 1);
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by Auto_tac;
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qed"length_append";
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Addsimps [length_append];
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Goal "length (map f xs) = length xs";
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by (induct_tac "xs" 1);
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by Auto_tac;
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qed "length_map";
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Addsimps [length_map];
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Goal "length(rev xs) = length(xs)";
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by (induct_tac "xs" 1);
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by Auto_tac;
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qed "length_rev";
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Addsimps [length_rev];
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Goal "xs ~= [] ==> length(tl xs) = (length xs) - 1";
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by (exhaust_tac "xs" 1);
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by Auto_tac;
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qed "length_tl";
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Addsimps [length_tl];
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Goal "(length xs = 0) = (xs = [])";
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by (induct_tac "xs" 1);
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by Auto_tac;
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qed "length_0_conv";
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AddIffs [length_0_conv];
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Goal "(0 = length xs) = (xs = [])";
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by (induct_tac "xs" 1);
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by Auto_tac;
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qed "zero_length_conv";
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AddIffs [zero_length_conv];
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Goal "(0 < length xs) = (xs ~= [])";
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by (induct_tac "xs" 1);
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by Auto_tac;
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qed "length_greater_0_conv";
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AddIffs [length_greater_0_conv];
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Goal "(length xs = Suc n) = (? y ys. xs = y#ys & length ys = n)";
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by (induct_tac "xs" 1);
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by (Auto_tac);
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qed "length_Suc_conv";
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AddIffs [length_Suc_conv];
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(** @ - append **)
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section "@ - append";
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Goal "(xs@ys)@zs = xs@(ys@zs)";
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by (induct_tac "xs" 1);
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by Auto_tac;
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qed "append_assoc";
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Addsimps [append_assoc];
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Goal "xs @ [] = xs";
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by (induct_tac "xs" 1);
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by Auto_tac;
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qed "append_Nil2";
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Addsimps [append_Nil2];
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Goal "(xs@ys = []) = (xs=[] & ys=[])";
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by (induct_tac "xs" 1);
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by Auto_tac;
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qed "append_is_Nil_conv";
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AddIffs [append_is_Nil_conv];
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Goal "([] = xs@ys) = (xs=[] & ys=[])";
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by (induct_tac "xs" 1);
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by Auto_tac;
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qed "Nil_is_append_conv";
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AddIffs [Nil_is_append_conv];
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Goal "(xs @ ys = xs) = (ys=[])";
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by (induct_tac "xs" 1);
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by Auto_tac;
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qed "append_self_conv";
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Goal "(xs = xs @ ys) = (ys=[])";
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by (induct_tac "xs" 1);
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by Auto_tac;
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qed "self_append_conv";
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AddIffs [append_self_conv,self_append_conv];
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Goal "!ys. length xs = length ys | length us = length vs \
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\              --> (xs@us = ys@vs) = (xs=ys & us=vs)";
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by (induct_tac "xs" 1);
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 by (rtac allI 1);
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 by (exhaust_tac "ys" 1);
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  by (Asm_simp_tac 1);
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 by (fast_tac (claset() addIs [less_add_Suc2] addss simpset()
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                      addEs [less_not_refl2 RSN (2,rev_notE)]) 1);
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by (rtac allI 1);
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by (exhaust_tac "ys" 1);
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by (fast_tac (claset() addIs [less_add_Suc2] 
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		       addss (simpset() delsimps [length_Suc_conv])
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                       addEs [(less_not_refl3) RSN (2,rev_notE)]) 1);
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by (Asm_simp_tac 1);
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qed_spec_mp "append_eq_append_conv";
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Addsimps [append_eq_append_conv];
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Goal "(xs @ ys = xs @ zs) = (ys=zs)";
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by (Simp_tac 1);
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qed "same_append_eq";
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Goal "(xs @ [x] = ys @ [y]) = (xs = ys & x = y)"; 
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by (Simp_tac 1);
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qed "append1_eq_conv";
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Goal "(ys @ xs = zs @ xs) = (ys=zs)";
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by (Simp_tac 1);
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qed "append_same_eq";
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AddSIs
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 [same_append_eq RS iffD2, append1_eq_conv RS iffD2, append_same_eq RS iffD2];
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AddSDs
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 [same_append_eq RS iffD1, append1_eq_conv RS iffD1, append_same_eq RS iffD1];
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Goal "(xs @ ys = ys) = (xs=[])";
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by (cut_inst_tac [("zs","[]")] append_same_eq 1);
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by Auto_tac;
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qed "append_self_conv2";
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Goal "(ys = xs @ ys) = (xs=[])";
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by (simp_tac (simpset() addsimps
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     [simplify (simpset()) (read_instantiate[("ys","[]")]append_same_eq)]) 1);
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by (Blast_tac 1);
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qed "self_append_conv2";
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AddIffs [append_self_conv2,self_append_conv2];
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Goal "xs ~= [] --> hd xs # tl xs = xs";
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by (induct_tac "xs" 1);
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by Auto_tac;
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qed_spec_mp "hd_Cons_tl";
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Addsimps [hd_Cons_tl];
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Goal "hd(xs@ys) = (if xs=[] then hd ys else hd xs)";
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by (induct_tac "xs" 1);
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by Auto_tac;
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qed "hd_append";
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Goal "xs ~= [] ==> hd(xs @ ys) = hd xs";
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by (asm_simp_tac (simpset() addsimps [hd_append]
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                           addsplits [list.split]) 1);
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qed "hd_append2";
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Addsimps [hd_append2];
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Goal "tl(xs@ys) = (case xs of [] => tl(ys) | z#zs => zs@ys)";
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by (simp_tac (simpset() addsplits [list.split]) 1);
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qed "tl_append";
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Goal "xs ~= [] ==> tl(xs @ ys) = (tl xs) @ ys";
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by (asm_simp_tac (simpset() addsimps [tl_append]
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                           addsplits [list.split]) 1);
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qed "tl_append2";
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Addsimps [tl_append2];
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(* trivial rules for solving @-equations automatically *)
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Goal "xs = ys ==> xs = [] @ ys";
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by (Asm_simp_tac 1);
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qed "eq_Nil_appendI";
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Goal "[| x#xs1 = ys; xs = xs1 @ zs |] ==> x#xs = ys@zs";
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by (dtac sym 1);
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by (Asm_simp_tac 1);
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qed "Cons_eq_appendI";
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Goal "[| xs@xs1 = zs; ys = xs1 @ us |] ==> xs@ys = zs@us";
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by (dtac sym 1);
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by (Asm_simp_tac 1);
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qed "append_eq_appendI";
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(***
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Simplification procedure for all list equalities.
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Currently only tries to rearranges @ to see if
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- both lists end in a singleton list,
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- or both lists end in the same list.
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***)
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local
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val list_eq_pattern =
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  read_cterm (sign_of List.thy) ("(xs::'a list) = ys",HOLogic.boolT);
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fun last (cons as Const("List.list.op #",_) $ _ $ xs) =
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      (case xs of Const("List.list.[]",_) => cons | _ => last xs)
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  | last (Const("List.op @",_) $ _ $ ys) = last ys
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  | last t = t;
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fun list1 (Const("List.list.op #",_) $ _ $ Const("List.list.[]",_)) = true
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  | list1 _ = false;
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fun butlast ((cons as Const("List.list.op #",_) $ x) $ xs) =
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      (case xs of Const("List.list.[]",_) => xs | _ => cons $ butlast xs)
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  | butlast ((app as Const("List.op @",_) $ xs) $ ys) = app $ butlast ys
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  | butlast xs = Const("List.list.[]",fastype_of xs);
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val rearr_tac =
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  simp_tac (HOL_basic_ss addsimps [append_assoc,append_Nil,append_Cons]);
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fun list_eq sg _ (F as (eq as Const(_,eqT)) $ lhs $ rhs) =
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  let
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    val lastl = last lhs and lastr = last rhs
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    fun rearr conv =
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      let val lhs1 = butlast lhs and rhs1 = butlast rhs
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          val Type(_,listT::_) = eqT
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          val appT = [listT,listT] ---> listT
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          val app = Const("List.op @",appT)
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          val F2 = eq $ (app$lhs1$lastl) $ (app$rhs1$lastr)
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          val ct = cterm_of sg (HOLogic.mk_Trueprop(HOLogic.mk_eq(F,F2)))
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          val thm = prove_goalw_cterm [] ct (K [rearr_tac 1])
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            handle ERROR =>
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            error("The error(s) above occurred while trying to prove " ^
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                  string_of_cterm ct)
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      in Some((conv RS (thm RS trans)) RS eq_reflection) end
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  in if list1 lastl andalso list1 lastr
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     then rearr append1_eq_conv
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     else
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     if lastl aconv lastr
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     then rearr append_same_eq
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     else None
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  end;
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in
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val list_eq_simproc = mk_simproc "list_eq" [list_eq_pattern] list_eq;
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end;
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Addsimprocs [list_eq_simproc];
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(** map **)
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section "map";
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Goal "(!x. x : set xs --> f x = g x) --> map f xs = map g xs";
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by (induct_tac "xs" 1);
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by Auto_tac;
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bind_thm("map_ext", impI RS (allI RS (result() RS mp)));
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Goal "map (%x. x) = (%xs. xs)";
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by (rtac ext 1);
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by (induct_tac "xs" 1);
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by Auto_tac;
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qed "map_ident";
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Addsimps[map_ident];
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Goal "map f (xs@ys) = map f xs @ map f ys";
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by (induct_tac "xs" 1);
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by Auto_tac;
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qed "map_append";
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Addsimps[map_append];
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Goalw [o_def] "map (f o g) xs = map f (map g xs)";
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by (induct_tac "xs" 1);
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by Auto_tac;
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qed "map_compose";
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Addsimps[map_compose];
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Goal "rev(map f xs) = map f (rev xs)";
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by (induct_tac "xs" 1);
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by Auto_tac;
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qed "rev_map";
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(* a congruence rule for map: *)
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Goal "(xs=ys) --> (!x. x : set ys --> f x = g x) --> map f xs = map g ys";
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by (rtac impI 1);
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by (hyp_subst_tac 1);
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by (induct_tac "ys" 1);
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by Auto_tac;
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   345
val lemma = result();
nipkow@3589
   346
bind_thm("map_cong",impI RSN (2,allI RSN (2,lemma RS mp RS mp)));
nipkow@3589
   347
nipkow@4935
   348
Goal "(map f xs = []) = (xs = [])";
wenzelm@4423
   349
by (induct_tac "xs" 1);
paulson@5316
   350
by Auto_tac;
nipkow@3860
   351
qed "map_is_Nil_conv";
nipkow@3860
   352
AddIffs [map_is_Nil_conv];
nipkow@3860
   353
nipkow@4935
   354
Goal "([] = map f xs) = (xs = [])";
wenzelm@4423
   355
by (induct_tac "xs" 1);
paulson@5316
   356
by Auto_tac;
nipkow@3860
   357
qed "Nil_is_map_conv";
nipkow@3860
   358
AddIffs [Nil_is_map_conv];
nipkow@3860
   359
nipkow@3860
   360
lcp@1169
   361
(** rev **)
lcp@1169
   362
nipkow@3467
   363
section "rev";
nipkow@3467
   364
nipkow@4935
   365
Goal "rev(xs@ys) = rev(ys) @ rev(xs)";
nipkow@3040
   366
by (induct_tac "xs" 1);
paulson@5316
   367
by Auto_tac;
lcp@1169
   368
qed "rev_append";
nipkow@2512
   369
Addsimps[rev_append];
lcp@1169
   370
nipkow@4935
   371
Goal "rev(rev l) = l";
nipkow@3040
   372
by (induct_tac "l" 1);
paulson@5316
   373
by Auto_tac;
lcp@1169
   374
qed "rev_rev_ident";
nipkow@2512
   375
Addsimps[rev_rev_ident];
lcp@1169
   376
nipkow@4935
   377
Goal "(rev xs = []) = (xs = [])";
wenzelm@4423
   378
by (induct_tac "xs" 1);
paulson@5316
   379
by Auto_tac;
nipkow@3860
   380
qed "rev_is_Nil_conv";
nipkow@3860
   381
AddIffs [rev_is_Nil_conv];
nipkow@3860
   382
nipkow@4935
   383
Goal "([] = rev xs) = (xs = [])";
wenzelm@4423
   384
by (induct_tac "xs" 1);
paulson@5316
   385
by Auto_tac;
nipkow@3860
   386
qed "Nil_is_rev_conv";
nipkow@3860
   387
AddIffs [Nil_is_rev_conv];
nipkow@3860
   388
nipkow@4935
   389
val prems = Goal "[| P []; !!x xs. P xs ==> P(xs@[x]) |] ==> P xs";
wenzelm@5132
   390
by (stac (rev_rev_ident RS sym) 1);
nipkow@4935
   391
br(read_instantiate [("P","%xs. ?P(rev xs)")]list.induct)1;
wenzelm@5132
   392
by (ALLGOALS Simp_tac);
wenzelm@5132
   393
by (resolve_tac prems 1);
wenzelm@5132
   394
by (eresolve_tac prems 1);
nipkow@4935
   395
qed "rev_induct";
nipkow@4935
   396
nipkow@5272
   397
fun rev_induct_tac xs = res_inst_tac [("xs",xs)] rev_induct;
nipkow@5272
   398
nipkow@4935
   399
Goal  "(xs = [] --> P) -->  (!ys y. xs = ys@[y] --> P) --> P";
wenzelm@5132
   400
by (res_inst_tac [("xs","xs")] rev_induct 1);
paulson@5316
   401
by Auto_tac;
nipkow@4935
   402
bind_thm ("rev_exhaust",
nipkow@4935
   403
  impI RSN (2,allI RSN (2,allI RSN (2,impI RS (result() RS mp RS mp)))));
nipkow@4935
   404
nipkow@2608
   405
nipkow@3465
   406
(** set **)
paulson@1812
   407
nipkow@3467
   408
section "set";
nipkow@3467
   409
oheimb@5296
   410
qed_goal "finite_set" thy "finite (set xs)" 
oheimb@5296
   411
	(K [induct_tac "xs" 1, Auto_tac]);
oheimb@5296
   412
Addsimps[finite_set];
oheimb@5296
   413
AddSIs[finite_set];
oheimb@5296
   414
nipkow@4935
   415
Goal "set (xs@ys) = (set xs Un set ys)";
nipkow@3040
   416
by (induct_tac "xs" 1);
paulson@5316
   417
by Auto_tac;
paulson@3647
   418
qed "set_append";
paulson@3647
   419
Addsimps[set_append];
paulson@1812
   420
nipkow@4935
   421
Goal "set l <= set (x#l)";
paulson@5316
   422
by Auto_tac;
paulson@3647
   423
qed "set_subset_Cons";
paulson@1936
   424
nipkow@4935
   425
Goal "(set xs = {}) = (xs = [])";
paulson@3457
   426
by (induct_tac "xs" 1);
paulson@5316
   427
by Auto_tac;
paulson@3647
   428
qed "set_empty";
paulson@3647
   429
Addsimps [set_empty];
nipkow@2608
   430
nipkow@4935
   431
Goal "set(rev xs) = set(xs)";
paulson@3457
   432
by (induct_tac "xs" 1);
paulson@5316
   433
by Auto_tac;
paulson@3647
   434
qed "set_rev";
paulson@3647
   435
Addsimps [set_rev];
nipkow@2608
   436
nipkow@4935
   437
Goal "set(map f xs) = f``(set xs)";
paulson@3457
   438
by (induct_tac "xs" 1);
paulson@5316
   439
by Auto_tac;
paulson@3647
   440
qed "set_map";
paulson@3647
   441
Addsimps [set_map];
nipkow@2608
   442
oheimb@5443
   443
Goal "(x : set (filter P xs)) = (x : set xs & P x)";
nipkow@4605
   444
by (induct_tac "xs" 1);
paulson@5316
   445
by Auto_tac;
nipkow@4605
   446
qed "in_set_filter";
nipkow@4605
   447
Addsimps [in_set_filter];
nipkow@4605
   448
nipkow@5272
   449
Goal "(x : set xs) = (? ys zs. xs = ys@x#zs)";
paulson@5318
   450
by (induct_tac "xs" 1);
paulson@5318
   451
 by (Simp_tac 1);
paulson@5318
   452
by (Asm_simp_tac 1);
paulson@5318
   453
by (rtac iffI 1);
paulson@5318
   454
by (blast_tac (claset() addIs [eq_Nil_appendI,Cons_eq_appendI]) 1);
paulson@5318
   455
by (REPEAT(etac exE 1));
paulson@5318
   456
by (exhaust_tac "ys" 1);
paulson@5316
   457
by Auto_tac;
nipkow@5272
   458
qed "in_set_conv_decomp";
nipkow@5272
   459
nipkow@5272
   460
(* eliminate `lists' in favour of `set' *)
nipkow@5272
   461
nipkow@5272
   462
Goal "(xs : lists A) = (!x : set xs. x : A)";
paulson@5318
   463
by (induct_tac "xs" 1);
paulson@5316
   464
by Auto_tac;
nipkow@5272
   465
qed "in_lists_conv_set";
nipkow@5272
   466
nipkow@5272
   467
bind_thm("in_listsD",in_lists_conv_set RS iffD1);
nipkow@5272
   468
AddSDs [in_listsD];
nipkow@5272
   469
bind_thm("in_listsI",in_lists_conv_set RS iffD2);
nipkow@5272
   470
AddSIs [in_listsI];
paulson@1812
   471
oheimb@5518
   472
(** mem **)
oheimb@5518
   473
 
oheimb@5518
   474
section "mem";
oheimb@5518
   475
oheimb@5518
   476
Goal "(x mem xs) = (x: set xs)";
oheimb@5518
   477
by (induct_tac "xs" 1);
oheimb@5518
   478
by Auto_tac;
oheimb@5518
   479
qed "set_mem_eq";
oheimb@5518
   480
oheimb@5518
   481
clasohm@923
   482
(** list_all **)
clasohm@923
   483
nipkow@3467
   484
section "list_all";
nipkow@3467
   485
oheimb@5518
   486
Goal "list_all P xs = (!x:set xs. P x)";
oheimb@5518
   487
by (induct_tac "xs" 1);
oheimb@5518
   488
by Auto_tac;
oheimb@5518
   489
qed "list_all_conv";
oheimb@5518
   490
oheimb@5443
   491
Goal "list_all P (xs@ys) = (list_all P xs & list_all P ys)";
nipkow@3040
   492
by (induct_tac "xs" 1);
paulson@5316
   493
by Auto_tac;
nipkow@2512
   494
qed "list_all_append";
nipkow@2512
   495
Addsimps [list_all_append];
clasohm@923
   496
clasohm@923
   497
nipkow@2608
   498
(** filter **)
clasohm@923
   499
nipkow@3467
   500
section "filter";
nipkow@3467
   501
nipkow@4935
   502
Goal "filter P (xs@ys) = filter P xs @ filter P ys";
paulson@3457
   503
by (induct_tac "xs" 1);
paulson@5316
   504
by Auto_tac;
nipkow@2608
   505
qed "filter_append";
nipkow@2608
   506
Addsimps [filter_append];
nipkow@2608
   507
nipkow@4935
   508
Goal "filter (%x. True) xs = xs";
nipkow@4605
   509
by (induct_tac "xs" 1);
paulson@5316
   510
by Auto_tac;
nipkow@4605
   511
qed "filter_True";
nipkow@4605
   512
Addsimps [filter_True];
nipkow@4605
   513
nipkow@4935
   514
Goal "filter (%x. False) xs = []";
nipkow@4605
   515
by (induct_tac "xs" 1);
paulson@5316
   516
by Auto_tac;
nipkow@4605
   517
qed "filter_False";
nipkow@4605
   518
Addsimps [filter_False];
nipkow@4605
   519
nipkow@4935
   520
Goal "length (filter P xs) <= length xs";
paulson@3457
   521
by (induct_tac "xs" 1);
paulson@5316
   522
by Auto_tac;
nipkow@4605
   523
qed "length_filter";
oheimb@5443
   524
Addsimps[length_filter];
nipkow@2608
   525
oheimb@5443
   526
Goal "set (filter P xs) <= set xs";
oheimb@5443
   527
by Auto_tac;
oheimb@5443
   528
qed "filter_is_subset";
oheimb@5443
   529
Addsimps [filter_is_subset];
oheimb@5443
   530
nipkow@2608
   531
nipkow@3467
   532
section "concat";
nipkow@3467
   533
nipkow@4935
   534
Goal  "concat(xs@ys) = concat(xs)@concat(ys)";
nipkow@3040
   535
by (induct_tac "xs" 1);
paulson@5316
   536
by Auto_tac;
nipkow@2608
   537
qed"concat_append";
nipkow@2608
   538
Addsimps [concat_append];
nipkow@2512
   539
nipkow@4935
   540
Goal "(concat xss = []) = (!xs:set xss. xs=[])";
wenzelm@4423
   541
by (induct_tac "xss" 1);
paulson@5316
   542
by Auto_tac;
nipkow@3896
   543
qed "concat_eq_Nil_conv";
nipkow@3896
   544
AddIffs [concat_eq_Nil_conv];
nipkow@3896
   545
nipkow@4935
   546
Goal "([] = concat xss) = (!xs:set xss. xs=[])";
wenzelm@4423
   547
by (induct_tac "xss" 1);
paulson@5316
   548
by Auto_tac;
nipkow@3896
   549
qed "Nil_eq_concat_conv";
nipkow@3896
   550
AddIffs [Nil_eq_concat_conv];
nipkow@3896
   551
nipkow@4935
   552
Goal  "set(concat xs) = Union(set `` set xs)";
nipkow@3467
   553
by (induct_tac "xs" 1);
paulson@5316
   554
by Auto_tac;
paulson@3647
   555
qed"set_concat";
paulson@3647
   556
Addsimps [set_concat];
nipkow@3467
   557
nipkow@4935
   558
Goal "map f (concat xs) = concat (map (map f) xs)"; 
nipkow@3467
   559
by (induct_tac "xs" 1);
paulson@5316
   560
by Auto_tac;
nipkow@3467
   561
qed "map_concat";
nipkow@3467
   562
nipkow@4935
   563
Goal "filter p (concat xs) = concat (map (filter p) xs)"; 
nipkow@3467
   564
by (induct_tac "xs" 1);
paulson@5316
   565
by Auto_tac;
nipkow@3467
   566
qed"filter_concat"; 
nipkow@3467
   567
nipkow@4935
   568
Goal "rev(concat xs) = concat (map rev (rev xs))";
nipkow@3467
   569
by (induct_tac "xs" 1);
paulson@5316
   570
by Auto_tac;
nipkow@2608
   571
qed "rev_concat";
clasohm@923
   572
clasohm@923
   573
(** nth **)
clasohm@923
   574
nipkow@3467
   575
section "nth";
nipkow@3467
   576
paulson@5278
   577
Goal "!xs. (xs@ys)!n = (if n < length xs then xs!n else ys!(n - length xs))";
berghofe@5183
   578
by (induct_tac "n" 1);
paulson@3457
   579
 by (Asm_simp_tac 1);
paulson@3457
   580
 by (rtac allI 1);
paulson@3457
   581
 by (exhaust_tac "xs" 1);
paulson@5316
   582
  by Auto_tac;
nipkow@2608
   583
qed_spec_mp "nth_append";
nipkow@2608
   584
nipkow@4935
   585
Goal "!n. n < length xs --> (map f xs)!n = f(xs!n)";
nipkow@3040
   586
by (induct_tac "xs" 1);
nipkow@1301
   587
(* case [] *)
nipkow@1301
   588
by (Asm_full_simp_tac 1);
nipkow@1301
   589
(* case x#xl *)
nipkow@1301
   590
by (rtac allI 1);
berghofe@5183
   591
by (induct_tac "n" 1);
paulson@5316
   592
by Auto_tac;
nipkow@1485
   593
qed_spec_mp "nth_map";
nipkow@1301
   594
Addsimps [nth_map];
nipkow@1301
   595
oheimb@5518
   596
Goal "!n. n < length xs --> Ball (set xs) P --> P(xs!n)";
nipkow@3040
   597
by (induct_tac "xs" 1);
nipkow@1301
   598
(* case [] *)
nipkow@1301
   599
by (Simp_tac 1);
nipkow@1301
   600
(* case x#xl *)
nipkow@1301
   601
by (rtac allI 1);
berghofe@5183
   602
by (induct_tac "n" 1);
paulson@5316
   603
by Auto_tac;
oheimb@5518
   604
qed_spec_mp "list_ball_nth";
nipkow@1301
   605
oheimb@5518
   606
Goal "!n. n < length xs --> xs!n : set xs";
nipkow@3040
   607
by (induct_tac "xs" 1);
nipkow@1301
   608
(* case [] *)
nipkow@1301
   609
by (Simp_tac 1);
nipkow@1301
   610
(* case x#xl *)
nipkow@1301
   611
by (rtac allI 1);
berghofe@5183
   612
by (induct_tac "n" 1);
nipkow@1301
   613
(* case 0 *)
nipkow@1301
   614
by (Asm_full_simp_tac 1);
nipkow@1301
   615
(* case Suc x *)
nipkow@4686
   616
by (Asm_full_simp_tac 1);
nipkow@1485
   617
qed_spec_mp "nth_mem";
nipkow@1301
   618
Addsimps [nth_mem];
nipkow@1301
   619
oheimb@5518
   620
nipkow@5077
   621
(** list update **)
nipkow@5077
   622
nipkow@5077
   623
section "list update";
nipkow@5077
   624
nipkow@5077
   625
Goal "!i. length(xs[i:=x]) = length xs";
nipkow@5077
   626
by (induct_tac "xs" 1);
nipkow@5077
   627
by (Simp_tac 1);
berghofe@5183
   628
by (asm_full_simp_tac (simpset() addsplits [nat.split]) 1);
nipkow@5077
   629
qed_spec_mp "length_list_update";
nipkow@5077
   630
Addsimps [length_list_update];
nipkow@5077
   631
nipkow@5077
   632
nipkow@3896
   633
(** last & butlast **)
nipkow@1327
   634
nipkow@4935
   635
Goal "last(xs@[x]) = x";
wenzelm@4423
   636
by (induct_tac "xs" 1);
paulson@5316
   637
by Auto_tac;
nipkow@3896
   638
qed "last_snoc";
nipkow@3896
   639
Addsimps [last_snoc];
nipkow@3896
   640
nipkow@4935
   641
Goal "butlast(xs@[x]) = xs";
wenzelm@4423
   642
by (induct_tac "xs" 1);
paulson@5316
   643
by Auto_tac;
nipkow@3896
   644
qed "butlast_snoc";
nipkow@3896
   645
Addsimps [butlast_snoc];
nipkow@3896
   646
nipkow@4935
   647
Goal "length(butlast xs) = length xs - 1";
nipkow@4935
   648
by (res_inst_tac [("xs","xs")] rev_induct 1);
paulson@5316
   649
by Auto_tac;
nipkow@4643
   650
qed "length_butlast";
nipkow@4643
   651
Addsimps [length_butlast];
nipkow@4643
   652
paulson@5278
   653
Goal "!ys. butlast (xs@ys) = (if ys=[] then butlast xs else xs@butlast ys)";
wenzelm@4423
   654
by (induct_tac "xs" 1);
paulson@5316
   655
by Auto_tac;
nipkow@3896
   656
qed_spec_mp "butlast_append";
nipkow@3896
   657
nipkow@4935
   658
Goal "x:set(butlast xs) --> x:set xs";
wenzelm@4423
   659
by (induct_tac "xs" 1);
paulson@5316
   660
by Auto_tac;
nipkow@3896
   661
qed_spec_mp "in_set_butlastD";
nipkow@3896
   662
paulson@5448
   663
Goal "x:set(butlast xs) | x:set(butlast ys) ==> x:set(butlast(xs@ys))";
paulson@5448
   664
by (auto_tac (claset() addDs [in_set_butlastD],
paulson@5448
   665
	      simpset() addsimps [butlast_append]));
paulson@5448
   666
qed "in_set_butlast_appendI";
nipkow@3902
   667
nipkow@2608
   668
(** take  & drop **)
nipkow@2608
   669
section "take & drop";
nipkow@1327
   670
nipkow@4935
   671
Goal "take 0 xs = []";
nipkow@3040
   672
by (induct_tac "xs" 1);
paulson@5316
   673
by Auto_tac;
nipkow@1327
   674
qed "take_0";
nipkow@1327
   675
nipkow@4935
   676
Goal "drop 0 xs = xs";
nipkow@3040
   677
by (induct_tac "xs" 1);
paulson@5316
   678
by Auto_tac;
nipkow@2608
   679
qed "drop_0";
nipkow@2608
   680
nipkow@4935
   681
Goal "take (Suc n) (x#xs) = x # take n xs";
paulson@1552
   682
by (Simp_tac 1);
nipkow@1419
   683
qed "take_Suc_Cons";
nipkow@1327
   684
nipkow@4935
   685
Goal "drop (Suc n) (x#xs) = drop n xs";
nipkow@2608
   686
by (Simp_tac 1);
nipkow@2608
   687
qed "drop_Suc_Cons";
nipkow@2608
   688
nipkow@2608
   689
Delsimps [take_Cons,drop_Cons];
nipkow@2608
   690
Addsimps [take_0,take_Suc_Cons,drop_0,drop_Suc_Cons];
nipkow@2608
   691
nipkow@4935
   692
Goal "!xs. length(take n xs) = min (length xs) n";
berghofe@5183
   693
by (induct_tac "n" 1);
paulson@5316
   694
 by Auto_tac;
paulson@3457
   695
by (exhaust_tac "xs" 1);
paulson@5316
   696
 by Auto_tac;
nipkow@2608
   697
qed_spec_mp "length_take";
nipkow@2608
   698
Addsimps [length_take];
clasohm@923
   699
nipkow@4935
   700
Goal "!xs. length(drop n xs) = (length xs - n)";
berghofe@5183
   701
by (induct_tac "n" 1);
paulson@5316
   702
 by Auto_tac;
paulson@3457
   703
by (exhaust_tac "xs" 1);
paulson@5316
   704
 by Auto_tac;
nipkow@2608
   705
qed_spec_mp "length_drop";
nipkow@2608
   706
Addsimps [length_drop];
nipkow@2608
   707
nipkow@4935
   708
Goal "!xs. length xs <= n --> take n xs = xs";
berghofe@5183
   709
by (induct_tac "n" 1);
paulson@5316
   710
 by Auto_tac;
paulson@3457
   711
by (exhaust_tac "xs" 1);
paulson@5316
   712
 by Auto_tac;
nipkow@2608
   713
qed_spec_mp "take_all";
clasohm@923
   714
nipkow@4935
   715
Goal "!xs. length xs <= n --> drop n xs = []";
berghofe@5183
   716
by (induct_tac "n" 1);
paulson@5316
   717
 by Auto_tac;
paulson@3457
   718
by (exhaust_tac "xs" 1);
paulson@5316
   719
 by Auto_tac;
nipkow@2608
   720
qed_spec_mp "drop_all";
nipkow@2608
   721
paulson@5278
   722
Goal "!xs. take n (xs @ ys) = (take n xs @ take (n - length xs) ys)";
berghofe@5183
   723
by (induct_tac "n" 1);
paulson@5316
   724
 by Auto_tac;
paulson@3457
   725
by (exhaust_tac "xs" 1);
paulson@5316
   726
 by Auto_tac;
nipkow@2608
   727
qed_spec_mp "take_append";
nipkow@2608
   728
Addsimps [take_append];
nipkow@2608
   729
nipkow@4935
   730
Goal "!xs. drop n (xs@ys) = drop n xs @ drop (n - length xs) ys"; 
berghofe@5183
   731
by (induct_tac "n" 1);
paulson@5316
   732
 by Auto_tac;
paulson@3457
   733
by (exhaust_tac "xs" 1);
paulson@5316
   734
 by Auto_tac;
nipkow@2608
   735
qed_spec_mp "drop_append";
nipkow@2608
   736
Addsimps [drop_append];
nipkow@2608
   737
nipkow@4935
   738
Goal "!xs n. take n (take m xs) = take (min n m) xs"; 
berghofe@5183
   739
by (induct_tac "m" 1);
paulson@5316
   740
 by Auto_tac;
paulson@3457
   741
by (exhaust_tac "xs" 1);
paulson@5316
   742
 by Auto_tac;
berghofe@5183
   743
by (exhaust_tac "na" 1);
paulson@5316
   744
 by Auto_tac;
nipkow@2608
   745
qed_spec_mp "take_take";
nipkow@2608
   746
nipkow@4935
   747
Goal "!xs. drop n (drop m xs) = drop (n + m) xs"; 
berghofe@5183
   748
by (induct_tac "m" 1);
paulson@5316
   749
 by Auto_tac;
paulson@3457
   750
by (exhaust_tac "xs" 1);
paulson@5316
   751
 by Auto_tac;
nipkow@2608
   752
qed_spec_mp "drop_drop";
clasohm@923
   753
nipkow@4935
   754
Goal "!xs n. take n (drop m xs) = drop m (take (n + m) xs)"; 
berghofe@5183
   755
by (induct_tac "m" 1);
paulson@5316
   756
 by Auto_tac;
paulson@3457
   757
by (exhaust_tac "xs" 1);
paulson@5316
   758
 by Auto_tac;
nipkow@2608
   759
qed_spec_mp "take_drop";
nipkow@2608
   760
nipkow@4935
   761
Goal "!xs. take n (map f xs) = map f (take n xs)"; 
berghofe@5183
   762
by (induct_tac "n" 1);
paulson@5316
   763
 by Auto_tac;
paulson@3457
   764
by (exhaust_tac "xs" 1);
paulson@5316
   765
 by Auto_tac;
nipkow@2608
   766
qed_spec_mp "take_map"; 
nipkow@2608
   767
nipkow@4935
   768
Goal "!xs. drop n (map f xs) = map f (drop n xs)"; 
berghofe@5183
   769
by (induct_tac "n" 1);
paulson@5316
   770
 by Auto_tac;
paulson@3457
   771
by (exhaust_tac "xs" 1);
paulson@5316
   772
 by Auto_tac;
nipkow@2608
   773
qed_spec_mp "drop_map";
nipkow@2608
   774
nipkow@4935
   775
Goal "!n i. i < n --> (take n xs)!i = xs!i";
paulson@3457
   776
by (induct_tac "xs" 1);
paulson@5316
   777
 by Auto_tac;
paulson@3457
   778
by (exhaust_tac "n" 1);
paulson@3457
   779
 by (Blast_tac 1);
paulson@3457
   780
by (exhaust_tac "i" 1);
paulson@5316
   781
 by Auto_tac;
nipkow@2608
   782
qed_spec_mp "nth_take";
nipkow@2608
   783
Addsimps [nth_take];
clasohm@923
   784
nipkow@4935
   785
Goal  "!xs i. n + i <= length xs --> (drop n xs)!i = xs!(n+i)";
berghofe@5183
   786
by (induct_tac "n" 1);
paulson@5316
   787
 by Auto_tac;
paulson@3457
   788
by (exhaust_tac "xs" 1);
paulson@5316
   789
 by Auto_tac;
nipkow@2608
   790
qed_spec_mp "nth_drop";
nipkow@2608
   791
Addsimps [nth_drop];
nipkow@2608
   792
nipkow@2608
   793
(** takeWhile & dropWhile **)
nipkow@2608
   794
nipkow@3467
   795
section "takeWhile & dropWhile";
nipkow@3467
   796
nipkow@4935
   797
Goal "takeWhile P xs @ dropWhile P xs = xs";
nipkow@3586
   798
by (induct_tac "xs" 1);
paulson@5316
   799
by Auto_tac;
nipkow@3586
   800
qed "takeWhile_dropWhile_id";
nipkow@3586
   801
Addsimps [takeWhile_dropWhile_id];
nipkow@3586
   802
nipkow@4935
   803
Goal  "x:set xs & ~P(x) --> takeWhile P (xs @ ys) = takeWhile P xs";
paulson@3457
   804
by (induct_tac "xs" 1);
paulson@5316
   805
by Auto_tac;
nipkow@2608
   806
bind_thm("takeWhile_append1", conjI RS (result() RS mp));
nipkow@2608
   807
Addsimps [takeWhile_append1];
clasohm@923
   808
nipkow@4935
   809
Goal "(!x:set xs. P(x)) --> takeWhile P (xs @ ys) = xs @ takeWhile P ys";
paulson@3457
   810
by (induct_tac "xs" 1);
paulson@5316
   811
by Auto_tac;
nipkow@2608
   812
bind_thm("takeWhile_append2", ballI RS (result() RS mp));
nipkow@2608
   813
Addsimps [takeWhile_append2];
lcp@1169
   814
nipkow@4935
   815
Goal "x:set xs & ~P(x) --> dropWhile P (xs @ ys) = (dropWhile P xs)@ys";
paulson@3457
   816
by (induct_tac "xs" 1);
paulson@5316
   817
by Auto_tac;
nipkow@2608
   818
bind_thm("dropWhile_append1", conjI RS (result() RS mp));
nipkow@2608
   819
Addsimps [dropWhile_append1];
nipkow@2608
   820
nipkow@4935
   821
Goal "(!x:set xs. P(x)) --> dropWhile P (xs @ ys) = dropWhile P ys";
paulson@3457
   822
by (induct_tac "xs" 1);
paulson@5316
   823
by Auto_tac;
nipkow@2608
   824
bind_thm("dropWhile_append2", ballI RS (result() RS mp));
nipkow@2608
   825
Addsimps [dropWhile_append2];
nipkow@2608
   826
nipkow@4935
   827
Goal "x:set(takeWhile P xs) --> x:set xs & P x";
paulson@3457
   828
by (induct_tac "xs" 1);
paulson@5316
   829
by Auto_tac;
paulson@3647
   830
qed_spec_mp"set_take_whileD";
nipkow@2608
   831
oheimb@4132
   832
qed_goal "zip_Nil_Nil"   thy "zip []     []     = []" (K [Simp_tac 1]);
oheimb@4132
   833
qed_goal "zip_Cons_Cons" thy "zip (x#xs) (y#ys) = (x,y)#zip xs ys" 
oheimb@4132
   834
						      (K [Simp_tac 1]);
nipkow@4605
   835
nipkow@5272
   836
nipkow@5272
   837
(** foldl **)
nipkow@5272
   838
section "foldl";
nipkow@5272
   839
nipkow@5272
   840
Goal "!a. foldl f a (xs @ ys) = foldl f (foldl f a xs) ys";
paulson@5318
   841
by (induct_tac "xs" 1);
paulson@5316
   842
by Auto_tac;
nipkow@5272
   843
qed_spec_mp "foldl_append";
nipkow@5272
   844
Addsimps [foldl_append];
nipkow@5272
   845
nipkow@5272
   846
(* Note: `n <= foldl op+ n ns' looks simpler, but is more difficult to use
nipkow@5272
   847
   because it requires an additional transitivity step
nipkow@5272
   848
*)
nipkow@5272
   849
Goal "!n::nat. m <= n --> m <= foldl op+ n ns";
paulson@5318
   850
by (induct_tac "ns" 1);
paulson@5318
   851
 by (Simp_tac 1);
paulson@5318
   852
by (Asm_full_simp_tac 1);
paulson@5318
   853
by (blast_tac (claset() addIs [trans_le_add1]) 1);
nipkow@5272
   854
qed_spec_mp "start_le_sum";
nipkow@5272
   855
nipkow@5272
   856
Goal "n : set ns ==> n <= foldl op+ 0 ns";
paulson@5318
   857
by (auto_tac (claset() addIs [start_le_sum],
nipkow@5272
   858
             simpset() addsimps [in_set_conv_decomp]));
nipkow@5272
   859
qed "elem_le_sum";
nipkow@5272
   860
nipkow@5272
   861
Goal "!m. (foldl op+ m ns = 0) = (m=0 & (!n : set ns. n=0))";
paulson@5318
   862
by (induct_tac "ns" 1);
paulson@5316
   863
by Auto_tac;
nipkow@5272
   864
qed_spec_mp "sum_eq_0_conv";
nipkow@5272
   865
AddIffs [sum_eq_0_conv];
nipkow@5272
   866
nipkow@5425
   867
(** upto **)
nipkow@5425
   868
nipkow@5427
   869
(* Does not terminate! *)
nipkow@5427
   870
Goal "[i..j(] = (if i<j then i#[Suc i..j(] else [])";
nipkow@5427
   871
by(induct_tac "j" 1);
nipkow@5427
   872
by Auto_tac;
nipkow@5427
   873
by(REPEAT(trans_tac 1));
nipkow@5427
   874
qed "upt_rec";
nipkow@5425
   875
nipkow@5427
   876
Goal "j<=i ==> [i..j(] = []";
nipkow@5427
   877
by(stac upt_rec 1);
nipkow@5427
   878
by(asm_simp_tac (simpset() addSolver cut_trans_tac) 1);
nipkow@5427
   879
qed "upt_conv_Nil";
nipkow@5427
   880
Addsimps [upt_conv_Nil];
nipkow@5427
   881
nipkow@5427
   882
Goal "i<=j ==> [i..(Suc j)(] = [i..j(]@[j]";
nipkow@5427
   883
by (Asm_simp_tac 1);
nipkow@5427
   884
qed "upt_Suc";
nipkow@5427
   885
nipkow@5427
   886
Goal "i<j ==> [i..j(] = i#[Suc i..j(]";
nipkow@5425
   887
br trans 1;
nipkow@5427
   888
by(stac upt_rec 1);
nipkow@5427
   889
br refl 2;
nipkow@5427
   890
by (Asm_simp_tac 1);
nipkow@5427
   891
qed "upt_conv_Cons";
nipkow@5427
   892
nipkow@5427
   893
Goal "length [i..j(] = j-i";
nipkow@5427
   894
by(induct_tac "j" 1);
nipkow@5427
   895
 by (Simp_tac 1);
nipkow@5427
   896
by(asm_simp_tac (simpset() addsimps [Suc_diff_le] addSolver cut_trans_tac) 1);
nipkow@5427
   897
qed "length_upt";
nipkow@5427
   898
Addsimps [length_upt];
nipkow@5425
   899
nipkow@5427
   900
Goal "i+k < j --> [i..j(] ! k = i+k";
nipkow@5427
   901
by(induct_tac "j" 1);
nipkow@5427
   902
 by(Simp_tac 1);
nipkow@5427
   903
by(asm_simp_tac (simpset() addsimps ([nth_append,less_diff_conv]@add_ac)
nipkow@5427
   904
                           addSolver cut_trans_tac) 1);
nipkow@5427
   905
br conjI 1;
nipkow@5427
   906
 by(Clarify_tac 1);
nipkow@5427
   907
 bd add_lessD1 1;
nipkow@5427
   908
 by(trans_tac 1);
nipkow@5427
   909
by(Clarify_tac 1);
nipkow@5427
   910
br conjI 1;
nipkow@5427
   911
 by(Clarify_tac 1);
nipkow@5427
   912
 by(subgoal_tac "n=i+k" 1);
nipkow@5427
   913
  by(Asm_full_simp_tac 1);
nipkow@5427
   914
 by(trans_tac 1);
nipkow@5427
   915
by(Clarify_tac 1);
nipkow@5427
   916
by(subgoal_tac "n=i+k" 1);
nipkow@5427
   917
 by(Asm_full_simp_tac 1);
nipkow@5427
   918
by(trans_tac 1);
nipkow@5427
   919
qed_spec_mp "nth_upt";
nipkow@5427
   920
Addsimps [nth_upt];
nipkow@5425
   921
nipkow@5272
   922
nipkow@4605
   923
(** nodups & remdups **)
nipkow@4605
   924
section "nodups & remdups";
nipkow@4605
   925
nipkow@4935
   926
Goal "set(remdups xs) = set xs";
nipkow@4605
   927
by (induct_tac "xs" 1);
nipkow@4605
   928
 by (Simp_tac 1);
nipkow@4686
   929
by (asm_full_simp_tac (simpset() addsimps [insert_absorb]) 1);
nipkow@4605
   930
qed "set_remdups";
nipkow@4605
   931
Addsimps [set_remdups];
nipkow@4605
   932
nipkow@4935
   933
Goal "nodups(remdups xs)";
nipkow@4605
   934
by (induct_tac "xs" 1);
paulson@5316
   935
by Auto_tac;
nipkow@4605
   936
qed "nodups_remdups";
nipkow@4605
   937
nipkow@4935
   938
Goal "nodups xs --> nodups (filter P xs)";
nipkow@4605
   939
by (induct_tac "xs" 1);
paulson@5316
   940
by Auto_tac;
nipkow@4605
   941
qed_spec_mp "nodups_filter";
nipkow@4605
   942
nipkow@3589
   943
(** replicate **)
nipkow@3589
   944
section "replicate";
nipkow@3589
   945
nipkow@4935
   946
Goal "set(replicate (Suc n) x) = {x}";
wenzelm@4423
   947
by (induct_tac "n" 1);
paulson@5316
   948
by Auto_tac;
nipkow@3589
   949
val lemma = result();
nipkow@3589
   950
nipkow@5043
   951
Goal "n ~= 0 ==> set(replicate n x) = {x}";
wenzelm@4423
   952
by (fast_tac (claset() addSDs [not0_implies_Suc] addSIs [lemma]) 1);
nipkow@3589
   953
qed "set_replicate";
nipkow@3589
   954
Addsimps [set_replicate];
nipkow@5162
   955
nipkow@5162
   956
nipkow@5281
   957
(*** Lexcicographic orderings on lists ***)
nipkow@5281
   958
section"Lexcicographic orderings on lists";
nipkow@5281
   959
nipkow@5281
   960
Goal "wf r ==> wf(lexn r n)";
paulson@5318
   961
by (induct_tac "n" 1);
paulson@5318
   962
by (Simp_tac 1);
paulson@5318
   963
by (Simp_tac 1);
paulson@5318
   964
by (rtac wf_subset 1);
paulson@5318
   965
by (rtac Int_lower1 2);
paulson@5318
   966
by (rtac wf_prod_fun_image 1);
paulson@5318
   967
by (rtac injI 2);
paulson@5318
   968
by (Auto_tac);
nipkow@5281
   969
qed "wf_lexn";
nipkow@5281
   970
nipkow@5281
   971
Goal "!xs ys. (xs,ys) : lexn r n --> length xs = n & length ys = n";
paulson@5318
   972
by (induct_tac "n" 1);
paulson@5318
   973
by (Auto_tac);
nipkow@5281
   974
qed_spec_mp "lexn_length";
nipkow@5281
   975
nipkow@5281
   976
Goalw [lex_def] "wf r ==> wf(lex r)";
paulson@5318
   977
by (rtac wf_UN 1);
paulson@5318
   978
by (blast_tac (claset() addIs [wf_lexn]) 1);
paulson@5318
   979
by (Clarify_tac 1);
paulson@5318
   980
by (rename_tac "m n" 1);
paulson@5318
   981
by (subgoal_tac "m ~= n" 1);
paulson@5318
   982
 by (Blast_tac 2);
paulson@5318
   983
by (blast_tac (claset() addDs [lexn_length,not_sym]) 1);
nipkow@5281
   984
qed "wf_lex";
nipkow@5281
   985
AddSIs [wf_lex];
nipkow@5281
   986
nipkow@5281
   987
Goal
nipkow@5281
   988
 "lexn r n = \
nipkow@5281
   989
\ {(xs,ys). length xs = n & length ys = n & \
nipkow@5281
   990
\           (? xys x y xs' ys'. xs= xys @ x#xs' & ys= xys @ y#ys' & (x,y):r)}";
paulson@5318
   991
by (induct_tac "n" 1);
paulson@5318
   992
 by (Simp_tac 1);
paulson@5318
   993
 by (Blast_tac 1);
paulson@5318
   994
by (asm_full_simp_tac (simpset() delsimps [length_Suc_conv] 
oheimb@5296
   995
				addsimps [lex_prod_def]) 1);
paulson@5318
   996
by (auto_tac (claset(), simpset() delsimps [length_Suc_conv]));
paulson@5318
   997
  by (Blast_tac 1);
paulson@5318
   998
 by (rename_tac "a xys x xs' y ys'" 1);
paulson@5318
   999
 by (res_inst_tac [("x","a#xys")] exI 1);
paulson@5318
  1000
 by (Simp_tac 1);
paulson@5318
  1001
by (exhaust_tac "xys" 1);
paulson@5318
  1002
 by (ALLGOALS (asm_full_simp_tac (simpset() delsimps [length_Suc_conv])));
paulson@5318
  1003
by (Blast_tac 1);
nipkow@5281
  1004
qed "lexn_conv";
nipkow@5281
  1005
nipkow@5281
  1006
Goalw [lex_def]
nipkow@5281
  1007
 "lex r = \
nipkow@5281
  1008
\ {(xs,ys). length xs = length ys & \
nipkow@5281
  1009
\           (? xys x y xs' ys'. xs= xys @ x#xs' & ys= xys @ y#ys' & (x,y):r)}";
paulson@5318
  1010
by (force_tac (claset(), simpset() delsimps [length_Suc_conv] addsimps [lexn_conv]) 1);
nipkow@5281
  1011
qed "lex_conv";
nipkow@5281
  1012
nipkow@5281
  1013
Goalw [lexico_def] "wf r ==> wf(lexico r)";
paulson@5318
  1014
by (Blast_tac 1);
nipkow@5281
  1015
qed "wf_lexico";
nipkow@5281
  1016
AddSIs [wf_lexico];
nipkow@5281
  1017
nipkow@5281
  1018
Goalw
nipkow@5281
  1019
 [lexico_def,diag_def,lex_prod_def,measure_def,inv_image_def]
nipkow@5281
  1020
"lexico r = {(xs,ys). length xs < length ys | \
nipkow@5281
  1021
\                     length xs = length ys & (xs,ys) : lex r}";
paulson@5318
  1022
by (Simp_tac 1);
nipkow@5281
  1023
qed "lexico_conv";
nipkow@5281
  1024
nipkow@5283
  1025
Goal "([],ys) ~: lex r";
paulson@5318
  1026
by (simp_tac (simpset() addsimps [lex_conv]) 1);
nipkow@5283
  1027
qed "Nil_notin_lex";
nipkow@5283
  1028
nipkow@5283
  1029
Goal "(xs,[]) ~: lex r";
paulson@5318
  1030
by (simp_tac (simpset() addsimps [lex_conv]) 1);
nipkow@5283
  1031
qed "Nil2_notin_lex";
nipkow@5283
  1032
nipkow@5283
  1033
AddIffs [Nil_notin_lex,Nil2_notin_lex];
nipkow@5283
  1034
nipkow@5283
  1035
Goal "((x#xs,y#ys) : lex r) = \
nipkow@5283
  1036
\     ((x,y) : r & length xs = length ys | x=y & (xs,ys) : lex r)";
paulson@5318
  1037
by (simp_tac (simpset() addsimps [lex_conv]) 1);
paulson@5318
  1038
by (rtac iffI 1);
paulson@5318
  1039
 by (blast_tac (claset() addIs [Cons_eq_appendI]) 2);
paulson@5318
  1040
by (REPEAT(eresolve_tac [conjE, exE] 1));
paulson@5318
  1041
by (exhaust_tac "xys" 1);
paulson@5318
  1042
by (Asm_full_simp_tac 1);
paulson@5318
  1043
by (Asm_full_simp_tac 1);
paulson@5318
  1044
by (Blast_tac 1);
nipkow@5283
  1045
qed "Cons_in_lex";
nipkow@5283
  1046
AddIffs [Cons_in_lex];