--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/Lex/NAe_of_RegExp.ML Mon Apr 27 16:46:56 1998 +0200
@@ -0,0 +1,663 @@
+(* Title: HOL/Lex/NAe_of_RegExp.ML
+ ID: $Id$
+ Author: Tobias Nipkow
+ Copyright 1998 TUM
+*)
+
+(******************************************************)
+(* atom *)
+(******************************************************)
+
+goalw thy [atom_def] "(fin (atom a) q) = (q = [False])";
+by(Simp_tac 1);
+qed "fin_atom";
+
+goalw thy [atom_def] "start (atom a) = [True]";
+by(Simp_tac 1);
+qed "start_atom";
+
+(* Use {x. False} = {}? *)
+
+goalw thy [atom_def,step_def]
+ "eps(atom a) = {}";
+by(Simp_tac 1);
+by (Blast_tac 1);
+qed "eps_atom";
+Addsimps [eps_atom];
+
+goalw thy [atom_def,step_def]
+ "(p,q) : step (atom a) (Some b) = (p=[True] & q=[False] & b=a)";
+by(Simp_tac 1);
+qed "in_step_atom_Some";
+Addsimps [in_step_atom_Some];
+
+goal thy
+ "([False],[False]) : steps (atom a) w = (w = [])";
+by (induct_tac "w" 1);
+ by(Simp_tac 1);
+by(asm_simp_tac (simpset() addsimps [comp_def]) 1);
+qed "False_False_in_steps_atom";
+
+goal thy
+ "(start (atom a), [False]) : steps (atom a) w = (w = [a])";
+by (induct_tac "w" 1);
+ by(asm_simp_tac (simpset() addsimps [start_atom,rtrancl_empty]) 1);
+by(asm_full_simp_tac (simpset()
+ addsimps [False_False_in_steps_atom,comp_def,start_atom]) 1);
+qed "start_fin_in_steps_atom";
+
+(******************************************************)
+(* union *)
+(******************************************************)
+
+(***** True/False ueber fin anheben *****)
+
+goalw thy [union_def]
+ "!L R. fin (union L R) (True#p) = fin L p";
+by (Simp_tac 1);
+qed_spec_mp "fin_union_True";
+
+goalw thy [union_def]
+ "!L R. fin (union L R) (False#p) = fin R p";
+by (Simp_tac 1);
+qed_spec_mp "fin_union_False";
+
+AddIffs [fin_union_True,fin_union_False];
+
+(***** True/False ueber step anheben *****)
+
+goalw thy [union_def,step_def]
+"!L R. (True#p,q) : step (union L R) a = (? r. q = True#r & (p,r) : step L a)";
+by (Simp_tac 1);
+by(Blast_tac 1);
+qed_spec_mp "True_in_step_union";
+
+goalw thy [union_def,step_def]
+"!L R. (False#p,q) : step (union L R) a = (? r. q = False#r & (p,r) : step R a)";
+by (Simp_tac 1);
+by(Blast_tac 1);
+qed_spec_mp "False_in_step_union";
+
+AddIffs [True_in_step_union,False_in_step_union];
+
+(***** True/False ueber epsclosure anheben *****)
+
+goal thy
+ "!!d. (tp,tq) : (eps(union L R))^* ==> \
+\ !p. tp = True#p --> (? q. (p,q) : (eps L)^* & tq = True#q)";
+be rtrancl_induct 1;
+ by(Blast_tac 1);
+by(Clarify_tac 1);
+by(Asm_full_simp_tac 1);
+by(blast_tac (claset() addIs [rtrancl_into_rtrancl]) 1);
+val lemma1a = result();
+
+goal thy
+ "!!d. (tp,tq) : (eps(union L R))^* ==> \
+\ !p. tp = False#p --> (? q. (p,q) : (eps R)^* & tq = False#q)";
+be rtrancl_induct 1;
+ by(Blast_tac 1);
+by(Clarify_tac 1);
+by(Asm_full_simp_tac 1);
+by(blast_tac (claset() addIs [rtrancl_into_rtrancl]) 1);
+val lemma1b = result();
+
+goal thy
+ "!!p. (p,q) : (eps L)^* ==> (True#p, True#q) : (eps(union L R))^*";
+be rtrancl_induct 1;
+ by(Blast_tac 1);
+by(blast_tac (claset() addIs [rtrancl_into_rtrancl]) 1);
+val lemma2a = result();
+
+goal thy
+ "!!p. (p,q) : (eps R)^* ==> (False#p, False#q) : (eps(union L R))^*";
+be rtrancl_induct 1;
+ by(Blast_tac 1);
+by(blast_tac (claset() addIs [rtrancl_into_rtrancl]) 1);
+val lemma2b = result();
+
+goal thy
+ "(True#p,q) : (eps(union L R))^* = (? r. q = True#r & (p,r) : (eps L)^*)";
+by(blast_tac (claset() addDs [lemma1a,lemma2a]) 1);
+qed "True_epsclosure_union";
+
+goal thy
+ "(False#p,q) : (eps(union L R))^* = (? r. q = False#r & (p,r) : (eps R)^*)";
+by(blast_tac (claset() addDs [lemma1b,lemma2b]) 1);
+qed "False_epsclosure_union";
+
+AddIffs [True_epsclosure_union,False_epsclosure_union];
+
+(***** True/False ueber steps anheben *****)
+
+goal thy
+ "!p. (True#p,q):steps (union L R) w = (? r. q = True # r & (p,r):steps L w)";
+by (induct_tac "w" 1);
+by (ALLGOALS Asm_simp_tac);
+(* Blast_tac produces PROOF FAILED for depth 8 *)
+by(Fast_tac 1);
+qed_spec_mp "lift_True_over_steps_union";
+
+goal thy
+ "!p. (False#p,q):steps (union L R) w = (? r. q = False#r & (p,r):steps R w)";
+by (induct_tac "w" 1);
+by (ALLGOALS Asm_simp_tac);
+(* Blast_tac produces PROOF FAILED for depth 8 *)
+by(Fast_tac 1);
+qed_spec_mp "lift_False_over_steps_union";
+
+AddIffs [lift_True_over_steps_union,lift_False_over_steps_union];
+
+
+(***** Epsilonhuelle des Startzustands *****)
+
+goal thy
+ "R^* = id Un (R^* O R)";
+by(rtac set_ext 1);
+by(split_all_tac 1);
+by(rtac iffI 1);
+ be rtrancl_induct 1;
+ by(Blast_tac 1);
+ by(blast_tac (claset() addIs [rtrancl_into_rtrancl]) 1);
+by(blast_tac (claset() addIs [rtrancl_into_rtrancl2]) 1);
+qed "unfold_rtrancl2";
+
+goal thy
+ "(p,q) : R^* = (q = p | (? r. (p,r) : R & (r,q) : R^*))";
+by(rtac (unfold_rtrancl2 RS equalityE) 1);
+by(Blast_tac 1);
+qed "in_unfold_rtrancl2";
+
+val epsclosure_start_step_union =
+ read_instantiate [("p","start(union L R)")] in_unfold_rtrancl2;
+AddIffs [epsclosure_start_step_union];
+
+goalw thy [union_def,step_def]
+ "!L R. (start(union L R),q) : eps(union L R) = \
+\ (q = True#start L | q = False#start R)";
+by(Simp_tac 1);
+qed_spec_mp "start_eps_union";
+AddIffs [start_eps_union];
+
+goalw thy [union_def,step_def]
+ "!L R. (start(union L R),q) ~: step (union L R) (Some a)";
+by(Simp_tac 1);
+qed_spec_mp "not_start_step_union_Some";
+AddIffs [not_start_step_union_Some];
+
+goal thy
+ "(start(union L R), q) : steps (union L R) w = \
+\ ( (w = [] & q = start(union L R)) | \
+\ (? p. q = True # p & (start L,p) : steps L w | \
+\ q = False # p & (start R,p) : steps R w) )";
+by (exhaust_tac "w" 1);
+ by (Asm_simp_tac 1);
+ (* Blast_tac produces PROOF FAILED! *)
+ by(Fast_tac 1);
+by (Asm_simp_tac 1);
+(* The goal is now completely dual to the first one.
+ Fast/Best_tac don't return. Blast_tac produces PROOF FAILED!
+ The lemmas used in the explicit proof are part of the claset already!
+*)
+br iffI 1;
+ by(Blast_tac 1);
+by(Clarify_tac 1);
+be disjE 1;
+ by(Blast_tac 1);
+by(Clarify_tac 1);
+br compI 1;
+br compI 1;
+br (epsclosure_start_step_union RS iffD2) 1;
+br disjI2 1;
+br exI 1;
+br conjI 1;
+br (start_eps_union RS iffD2) 1;
+br disjI2 1;
+br refl 1;
+by(Clarify_tac 1);
+br exI 1;
+br conjI 1;
+br refl 1;
+ba 1;
+by(Clarify_tac 1);
+br exI 1;
+br conjI 1;
+br refl 1;
+ba 1;
+by(Clarify_tac 1);
+br exI 1;
+br conjI 1;
+br refl 1;
+ba 1;
+qed "steps_union";
+
+goalw thy [union_def]
+ "!L R. ~ fin (union L R) (start(union L R))";
+by(Simp_tac 1);
+qed_spec_mp "start_union_not_final";
+AddIffs [start_union_not_final];
+
+goalw thy [accepts_def]
+ "accepts (union L R) w = (accepts L w | accepts R w)";
+by (simp_tac (simpset() addsimps [steps_union]) 1);
+auto();
+qed "final_union";
+
+
+(******************************************************)
+(* conc *)
+(******************************************************)
+
+(** True/False in fin **)
+
+goalw thy [conc_def]
+ "!L R. fin (conc L R) (True#p) = False";
+by (Simp_tac 1);
+qed_spec_mp "fin_conc_True";
+
+goalw thy [conc_def]
+ "!L R. fin (conc L R) (False#p) = fin R p";
+by (Simp_tac 1);
+qed "fin_conc_False";
+
+AddIffs [fin_conc_True,fin_conc_False];
+
+(** True/False in step **)
+
+goalw thy [conc_def,step_def]
+ "!L R. (True#p,q) : step (conc L R) a = \
+\ ((? r. q=True#r & (p,r): step L a) | \
+\ (fin L p & a=None & q=False#start R))";
+by (Simp_tac 1);
+by(Blast_tac 1);
+qed_spec_mp "True_step_conc";
+
+goalw thy [conc_def,step_def]
+ "!L R. (False#p,q) : step (conc L R) a = \
+\ (? r. q = False#r & (p,r) : step R a)";
+by (Simp_tac 1);
+by(Blast_tac 1);
+qed_spec_mp "False_step_conc";
+
+AddIffs [True_step_conc, False_step_conc];
+
+(** False in epsclosure **)
+
+goal thy
+ "!!d. (tp,tq) : (eps(conc L R))^* ==> \
+\ !p. tp = False#p --> (? q. (p,q) : (eps R)^* & tq = False#q)";
+by(etac rtrancl_induct 1);
+ by(Blast_tac 1);
+by(blast_tac (claset() addIs [rtrancl_into_rtrancl]) 1);
+qed "lemma1b";
+
+goal thy
+ "!!p. (p,q) : (eps R)^* ==> (False#p, False#q) : (eps(conc L R))^*";
+by(etac rtrancl_induct 1);
+ by(Blast_tac 1);
+by(blast_tac (claset() addIs [rtrancl_into_rtrancl]) 1);
+val lemma2b = result();
+
+goal thy
+ "((False # p, q) : (eps (conc L R))^*) = \
+\ (? r. q = False # r & (p, r) : (eps R)^*)";
+by (rtac iffI 1);
+ by(blast_tac (claset() addDs [lemma1b]) 1);
+by(blast_tac (claset() addDs [lemma2b]) 1);
+qed "False_epsclosure_conc";
+AddIffs [False_epsclosure_conc];
+
+(** False in steps **)
+
+goal thy
+ "!p. (False#p,q): steps (conc L R) w = (? r. q=False#r & (p,r): steps R w)";
+by (induct_tac "w" 1);
+ by (Simp_tac 1);
+by (Simp_tac 1);
+(* Blast_tac produces PROOF FAILED for depth 8 *)
+by(Fast_tac 1);
+qed_spec_mp "False_steps_conc";
+AddIffs [False_steps_conc];
+
+(** True in epsclosure **)
+
+goal thy
+ "!!L R. (p,q): (eps L)^* ==> (True#p,True#q) : (eps(conc L R))^*";
+be rtrancl_induct 1;
+ by(Blast_tac 1);
+by(blast_tac (claset() addIs [rtrancl_into_rtrancl]) 1);
+qed "True_True_eps_concI";
+
+goal thy
+ "!!L R. !p. (p,q) : steps L w --> (True#p,True#q) : steps (conc L R) w";
+by(induct_tac "w" 1);
+ by (simp_tac (simpset() addsimps [True_True_eps_concI]) 1);
+by (Simp_tac 1);
+by(blast_tac (claset() addIs [True_True_eps_concI]) 1);
+qed_spec_mp "True_True_steps_concI";
+
+goal thy
+ "!!d. (tp,tq) : (eps(conc L R))^* ==> \
+\ !p. tp = True#p --> \
+\ (? q. tq = True#q & (p,q) : (eps L)^*) | \
+\ (? q r. tq = False#q & (p,r):(eps L)^* & fin L r & (start R,q) : (eps R)^*)";
+by(etac rtrancl_induct 1);
+ by(Blast_tac 1);
+by(blast_tac (claset() addIs [rtrancl_into_rtrancl]) 1);
+val lemma1a = result();
+
+goal thy
+ "!!p. (p, q) : (eps L)^* ==> (True#p, True#q) : (eps(conc L R))^*";
+by(etac rtrancl_induct 1);
+ by(Blast_tac 1);
+by(blast_tac (claset() addIs [rtrancl_into_rtrancl]) 1);
+val lemma2a = result();
+
+goalw thy [conc_def,step_def]
+ "!!L R. (p,q) : step R None ==> (False#p, False#q) : step (conc L R) None";
+by(split_all_tac 1);
+by (Asm_full_simp_tac 1);
+val lemma = result();
+
+goal thy
+ "!!L R. (p,q) : (eps R)^* ==> (False#p, False#q) : (eps(conc L R))^*";
+by(etac rtrancl_induct 1);
+ by(Blast_tac 1);
+by (dtac lemma 1);
+by(blast_tac (claset() addIs [rtrancl_into_rtrancl]) 1);
+val lemma2b = result();
+
+goalw thy [conc_def,step_def]
+ "!!L R. fin L p ==> (True#p, False#start R) : eps(conc L R)";
+by(split_all_tac 1);
+by(Asm_full_simp_tac 1);
+qed "True_False_eps_concI";
+
+goal thy
+ "((True#p,q) : (eps(conc L R))^*) = \
+\ ((? r. (p,r) : (eps L)^* & q = True#r) | \
+\ (? r. (p,r) : (eps L)^* & fin L r & \
+\ (? s. (start R, s) : (eps R)^* & q = False#s)))";
+by(rtac iffI 1);
+ by(blast_tac (claset() addDs [lemma1a]) 1);
+be disjE 1;
+ by(blast_tac (claset() addIs [lemma2a]) 1);
+by(Clarify_tac 1);
+br (rtrancl_trans) 1;
+be lemma2a 1;
+br (rtrancl_into_rtrancl2) 1;
+be True_False_eps_concI 1;
+be lemma2b 1;
+qed "True_epsclosure_conc";
+AddIffs [True_epsclosure_conc];
+
+(** True in steps **)
+
+goal thy
+ "!p. (True#p,q) : steps (conc L R) w --> \
+\ ((? r. (p,r) : steps L w & q = True#r) | \
+\ (? u v. w = u@v & (? r. (p,r) : steps L u & fin L r & \
+\ (? s. (start R,s) : steps R v & q = False#s))))";
+by(induct_tac "w" 1);
+ by(Simp_tac 1);
+by(Simp_tac 1);
+by(clarify_tac (claset() delrules [disjCI]) 1);
+ be disjE 1;
+ by(clarify_tac (claset() delrules [disjCI]) 1);
+ be disjE 1;
+ by(clarify_tac (claset() delrules [disjCI]) 1);
+ by(etac allE 1 THEN mp_tac 1);
+ be disjE 1;
+ by (Blast_tac 1);
+ br disjI2 1;
+ by (Clarify_tac 1);
+ by(Simp_tac 1);
+ by(res_inst_tac[("x","a#u")] exI 1);
+ by(Simp_tac 1);
+ by (Blast_tac 1);
+ by (Blast_tac 1);
+br disjI2 1;
+by (Clarify_tac 1);
+by(Simp_tac 1);
+by(res_inst_tac[("x","[]")] exI 1);
+by(Simp_tac 1);
+by (Blast_tac 1);
+qed_spec_mp "True_steps_concD";
+
+goal thy
+ "(True#p,q) : steps (conc L R) w = \
+\ ((? r. (p,r) : steps L w & q = True#r) | \
+\ (? u v. w = u@v & (? r. (p,r) : steps L u & fin L r & \
+\ (? s. (start R,s) : steps R v & q = False#s))))";
+by(blast_tac (claset() addDs [True_steps_concD]
+ addIs [True_True_steps_concI,in_steps_epsclosure,r_into_rtrancl]) 1);
+qed "True_steps_conc";
+
+(** starting from the start **)
+
+goalw thy [conc_def]
+ "!L R. start(conc L R) = True#start L";
+by(Simp_tac 1);
+qed_spec_mp "start_conc";
+
+goalw thy [conc_def]
+ "!L R. fin(conc L R) p = (? s. p = False#s & fin R s)";
+by (simp_tac (simpset() addsplits [split_list_case]) 1);
+qed_spec_mp "final_conc";
+
+
+(******************************************************)
+(* star *)
+(******************************************************)
+
+goalw thy [star_def,step_def]
+ "!A. (True#p,q) : eps(star A) = \
+\ ( (? r. q = True#r & (p,r) : eps A) | (fin A p & q = True#start A) )";
+by(Simp_tac 1);
+by(Blast_tac 1);
+qed_spec_mp "True_in_eps_star";
+AddIffs [True_in_eps_star];
+
+goalw thy [star_def,step_def]
+ "!A. (p,q) : step A a --> (True#p, True#q) : step (star A) a";
+by(Simp_tac 1);
+qed_spec_mp "True_True_step_starI";
+
+goal thy
+ "!!A. (p,r) : (eps A)^* ==> (True#p, True#r) : (eps(star A))^*";
+be rtrancl_induct 1;
+ by(Blast_tac 1);
+by(blast_tac (claset() addIs [True_True_step_starI,rtrancl_into_rtrancl]) 1);
+qed_spec_mp "True_True_eps_starI";
+
+goalw thy [star_def,step_def]
+ "!A. fin A p --> (True#p,True#start A) : eps(star A)";
+by(Simp_tac 1);
+qed_spec_mp "True_start_eps_starI";
+
+goal thy
+ "!!dummy. (tp,s) : (eps(star A))^* ==> (! p. tp = True#p --> \
+\ (? r. ((p,r) : (eps A)^* | \
+\ (? q. (p,q) : (eps A)^* & fin A q & (start A,r) : (eps A)^*)) & \
+\ s = True#r))";
+be rtrancl_induct 1;
+ by(Simp_tac 1);
+by (Clarify_tac 1);
+by (Asm_full_simp_tac 1);
+by(blast_tac (claset() addIs [rtrancl_into_rtrancl]) 1);
+val lemma = result();
+
+goal thy
+ "((True#p,s) : (eps(star A))^*) = \
+\ (? r. ((p,r) : (eps A)^* | \
+\ (? q. (p,q) : (eps A)^* & fin A q & (start A,r) : (eps A)^*)) & \
+\ s = True#r)";
+br iffI 1;
+ bd lemma 1;
+ by(Blast_tac 1);
+(* Why can't blast_tac do the rest? *)
+by (Clarify_tac 1);
+be disjE 1;
+be True_True_eps_starI 1;
+by (Clarify_tac 1);
+br rtrancl_trans 1;
+be True_True_eps_starI 1;
+br rtrancl_trans 1;
+br r_into_rtrancl 1;
+be True_start_eps_starI 1;
+be True_True_eps_starI 1;
+qed "True_eps_star";
+AddIffs [True_eps_star];
+
+(** True in step Some **)
+
+goalw thy [star_def,step_def]
+ "!A. (True#p,r): step (star A) (Some a) = \
+\ (? q. (p,q): step A (Some a) & r=True#q)";
+by(Simp_tac 1);
+by(Blast_tac 1);
+qed_spec_mp "True_step_star";
+AddIffs [True_step_star];
+
+
+(** True in steps **)
+
+(* reverse list induction! Complicates matters for conc? *)
+goal thy
+ "!rr. (True#start A,rr) : steps (star A) w --> \
+\ (? us v. w = concat us @ v & \
+\ (!u:set us. accepts A u) & \
+\ (? r. (start A,r) : steps A v & rr = True#r))";
+by(res_inst_tac [("xs","w")] snoc_induct 1);
+ by (Asm_full_simp_tac 1);
+ by (Clarify_tac 1);
+ by(res_inst_tac [("x","[]")] exI 1);
+ be disjE 1;
+ by (Asm_simp_tac 1);
+ by (Clarify_tac 1);
+ by (Asm_simp_tac 1);
+by(simp_tac (simpset() addsimps [O_assoc,epsclosure_steps]) 1);
+by (Clarify_tac 1);
+by(etac allE 1 THEN mp_tac 1);
+by (Clarify_tac 1);
+be disjE 1;
+ by(res_inst_tac [("x","us")] exI 1);
+ by(res_inst_tac [("x","v@[x]")] exI 1);
+ by(asm_simp_tac (simpset() addsimps [O_assoc,epsclosure_steps]) 1);
+ by(Blast_tac 1);
+by (Clarify_tac 1);
+by(res_inst_tac [("x","us@[v@[x]]")] exI 1);
+by(res_inst_tac [("x","[]")] exI 1);
+by(asm_full_simp_tac (simpset() addsimps [accepts_def]) 1);
+by(Blast_tac 1);
+qed_spec_mp "True_start_steps_starD";
+
+goal thy "!p. (p,q) : steps A w --> (True#p,True#q) : steps (star A) w";
+by(induct_tac "w" 1);
+ by(Simp_tac 1);
+by(Simp_tac 1);
+by(blast_tac (claset() addIs [True_True_eps_starI,True_True_step_starI]) 1);
+qed_spec_mp "True_True_steps_starI";
+
+goalw thy [accepts_def]
+ "(!u : set us. accepts A u) --> \
+\ (True#start A,True#start A) : steps (star A) (concat us)";
+by(induct_tac "us" 1);
+ by(Simp_tac 1);
+by(Simp_tac 1);
+by(blast_tac (claset() addIs [True_True_steps_starI,True_start_eps_starI,r_into_rtrancl,in_epsclosure_steps]) 1);
+qed_spec_mp "steps_star_cycle";
+
+(* Better stated directly with start(star A)? Loop in star A back to start(star A)?*)
+goal thy
+ "(True#start A,rr) : steps (star A) w = \
+\ (? us v. w = concat us @ v & \
+\ (!u:set us. accepts A u) & \
+\ (? r. (start A,r) : steps A v & rr = True#r))";
+br iffI 1;
+ be True_start_steps_starD 1;
+by (Clarify_tac 1);
+by(Asm_simp_tac 1);
+by(blast_tac (claset() addIs [True_True_steps_starI,steps_star_cycle]) 1);
+qed "True_start_steps_star";
+
+(** the start state **)
+
+goalw thy [star_def,step_def]
+ "!A. (start(star A),r) : step (star A) a = (a=None & r = True#start A)";
+by(Simp_tac 1);
+qed_spec_mp "start_step_star";
+AddIffs [start_step_star];
+
+val epsclosure_start_step_star =
+ read_instantiate [("p","start(star A)")] in_unfold_rtrancl2;
+
+goal thy
+ "(start(star A),r) : steps (star A) w = \
+\ ((w=[] & r= start(star A)) | (True#start A,r) : steps (star A) w)";
+br iffI 1;
+ by(exhaust_tac "w" 1);
+ by(asm_full_simp_tac (simpset() addsimps
+ [epsclosure_start_step_star]) 1);
+ by(Asm_full_simp_tac 1);
+ by (Clarify_tac 1);
+ by(asm_full_simp_tac (simpset() addsimps
+ [epsclosure_start_step_star]) 1);
+ by(Blast_tac 1);
+be disjE 1;
+ by(Asm_simp_tac 1);
+by(blast_tac (claset() addIs [in_steps_epsclosure,r_into_rtrancl]) 1);
+qed "start_steps_star";
+
+goalw thy [star_def] "!A. fin (star A) (True#p) = fin A p";
+by(Simp_tac 1);
+qed_spec_mp "fin_star_True";
+AddIffs [fin_star_True];
+
+goalw thy [star_def] "!A. fin (star A) (start(star A))";
+by(Simp_tac 1);
+qed_spec_mp "fin_star_start";
+AddIffs [fin_star_start];
+
+(* too complex! Simpler if loop back to start(star A)? *)
+goalw thy [accepts_def]
+ "accepts (star A) w = \
+\ (? us. (!u : set(us). accepts A u) & (w = concat us) )";
+by(simp_tac (simpset() addsimps [start_steps_star,True_start_steps_star]) 1);
+br iffI 1;
+ by (Clarify_tac 1);
+ be disjE 1;
+ by (Clarify_tac 1);
+ by(Simp_tac 1);
+ by(res_inst_tac [("x","[]")] exI 1);
+ by(Simp_tac 1);
+ by (Clarify_tac 1);
+ by(res_inst_tac [("x","us@[v]")] exI 1);
+ by(asm_full_simp_tac (simpset() addsimps [accepts_def]) 1);
+ by(Blast_tac 1);
+by (Clarify_tac 1);
+by(res_inst_tac [("xs","us")] snoc_exhaust 1);
+ by(Asm_simp_tac 1);
+ by(Blast_tac 1);
+by (Clarify_tac 1);
+by(asm_full_simp_tac (simpset() addsimps [accepts_def]) 1);
+by(Blast_tac 1);
+qed "accepts_star";
+
+
+(***** Correctness of r2n *****)
+
+goal thy
+ "!w. w:(lang r) = accepts (r2n r) w";
+by(induct_tac "r" 1);
+ by(simp_tac (simpset() addsimps [accepts_def]) 1);
+ by(simp_tac(simpset() addsimps
+ [accepts_def,start_fin_in_steps_atom,fin_atom]) 1);
+ (* 3. Fall: Union *)
+ by (asm_simp_tac (simpset() addsimps [final_union]) 1);
+ (* 4. Fall: Concat *)
+ by (asm_simp_tac (simpset() addsimps
+ [accepts_def,True_steps_conc,final_conc,start_conc,RegSet.conc_def]) 1);
+ by(Blast_tac 1);
+by (asm_simp_tac (simpset() addsimps [in_star,accepts_star]) 1);
+qed "Rexp_Automata";