# HG changeset patch # User Cezary Kaliszyk # Date 1277275361 -7200 # Node ID ab36b1a50ca8f5e087f156cb7c1303b41d8f8fdb # Parent b5989aa323582bda264a081cd8c503611ef1ddfb Replace 'list_rel' by 'list_all2'; they are equivalent. diff -r b5989aa32358 -r ab36b1a50ca8 src/HOL/Library/Quotient_List.thy --- a/src/HOL/Library/Quotient_List.thy Tue Jun 22 19:46:16 2010 +0200 +++ b/src/HOL/Library/Quotient_List.thy Wed Jun 23 08:42:41 2010 +0200 @@ -8,15 +8,7 @@ imports Main Quotient_Syntax begin -fun - list_rel -where - "list_rel R [] [] = True" -| "list_rel R (x#xs) [] = False" -| "list_rel R [] (x#xs) = False" -| "list_rel R (x#xs) (y#ys) = (R x y \ list_rel R xs ys)" - -declare [[map list = (map, list_rel)]] +declare [[map list = (map, list_all2)]] lemma split_list_all: shows "(\x. P x) \ P [] \ (\x xs. P (x#xs))" @@ -33,52 +25,47 @@ apply(simp_all) done +lemma list_all2_reflp: + shows "equivp R \ list_all2 R xs xs" + by (induct xs, simp_all add: equivp_reflp) -lemma list_rel_reflp: - shows "equivp R \ list_rel R xs xs" - apply(induct xs) - apply(simp_all add: equivp_reflp) - done - -lemma list_rel_symp: +lemma list_all2_symp: assumes a: "equivp R" - shows "list_rel R xs ys \ list_rel R ys xs" - apply(induct xs ys rule: list_induct2') + and b: "list_all2 R xs ys" + shows "list_all2 R ys xs" + using list_all2_lengthD[OF b] b + apply(induct xs ys rule: list_induct2) apply(simp_all) apply(rule equivp_symp[OF a]) apply(simp) done -lemma list_rel_transp: +thm list_induct3 + +lemma list_all2_transp: assumes a: "equivp R" - shows "list_rel R xs1 xs2 \ list_rel R xs2 xs3 \ list_rel R xs1 xs3" - using a - apply(induct R xs1 xs2 arbitrary: xs3 rule: list_rel.induct) - apply(simp) - apply(simp) - apply(simp) - apply(case_tac xs3) - apply(clarify) - apply(simp (no_asm_use)) - apply(clarify) - apply(simp (no_asm_use)) - apply(auto intro: equivp_transp) + and b: "list_all2 R xs1 xs2" + and c: "list_all2 R xs2 xs3" + shows "list_all2 R xs1 xs3" + using list_all2_lengthD[OF b] list_all2_lengthD[OF c] b c + apply(induct rule: list_induct3) + apply(simp_all) + apply(auto intro: equivp_transp[OF a]) done lemma list_equivp[quot_equiv]: assumes a: "equivp R" - shows "equivp (list_rel R)" - apply(rule equivpI) + shows "equivp (list_all2 R)" + apply (intro equivpI) unfolding reflp_def symp_def transp_def - apply(subst split_list_all) - apply(simp add: equivp_reflp[OF a] list_rel_reflp[OF a]) - apply(blast intro: list_rel_symp[OF a]) - apply(blast intro: list_rel_transp[OF a]) + apply(simp add: list_all2_reflp[OF a]) + apply(blast intro: list_all2_symp[OF a]) + apply(blast intro: list_all2_transp[OF a]) done -lemma list_rel_rel: +lemma list_all2_rel: assumes q: "Quotient R Abs Rep" - shows "list_rel R r s = (list_rel R r r \ list_rel R s s \ (map Abs r = map Abs s))" + shows "list_all2 R r s = (list_all2 R r r \ list_all2 R s s \ (map Abs r = map Abs s))" apply(induct r s rule: list_induct2') apply(simp_all) using Quotient_rel[OF q] @@ -87,21 +74,16 @@ lemma list_quotient[quot_thm]: assumes q: "Quotient R Abs Rep" - shows "Quotient (list_rel R) (map Abs) (map Rep)" + shows "Quotient (list_all2 R) (map Abs) (map Rep)" unfolding Quotient_def apply(subst split_list_all) apply(simp add: Quotient_abs_rep[OF q] abs_o_rep[OF q] map_id) - apply(rule conjI) - apply(rule allI) + apply(intro conjI allI) apply(induct_tac a) - apply(simp) - apply(simp) - apply(simp add: Quotient_rep_reflp[OF q]) - apply(rule allI)+ - apply(rule list_rel_rel[OF q]) + apply(simp_all add: Quotient_rep_reflp[OF q]) + apply(rule list_all2_rel[OF q]) done - lemma cons_prs_aux: assumes q: "Quotient R Abs Rep" shows "(map Abs) ((Rep h) # (map Rep t)) = h # t" @@ -115,7 +97,7 @@ lemma cons_rsp[quot_respect]: assumes q: "Quotient R Abs Rep" - shows "(R ===> list_rel R ===> list_rel R) (op #) (op #)" + shows "(R ===> list_all2 R ===> list_all2 R) (op #) (op #)" by (auto) lemma nil_prs[quot_preserve]: @@ -125,7 +107,7 @@ lemma nil_rsp[quot_respect]: assumes q: "Quotient R Abs Rep" - shows "list_rel R [] []" + shows "list_all2 R [] []" by simp lemma map_prs_aux: @@ -146,8 +128,8 @@ lemma map_rsp[quot_respect]: assumes q1: "Quotient R1 Abs1 Rep1" and q2: "Quotient R2 Abs2 Rep2" - shows "((R1 ===> R2) ===> (list_rel R1) ===> list_rel R2) map map" - and "((R1 ===> op =) ===> (list_rel R1) ===> op =) map map" + shows "((R1 ===> R2) ===> (list_all2 R1) ===> list_all2 R2) map map" + and "((R1 ===> op =) ===> (list_all2 R1) ===> op =) map map" apply simp_all apply(rule_tac [!] allI)+ apply(rule_tac [!] impI) @@ -183,53 +165,45 @@ by (simp only: expand_fun_eq fun_map_def foldl_prs_aux[OF a b]) (simp) -lemma list_rel_empty: - shows "list_rel R [] b \ length b = 0" +lemma list_all2_empty: + shows "list_all2 R [] b \ length b = 0" by (induct b) (simp_all) -lemma list_rel_len: - shows "list_rel R a b \ length a = length b" - apply (induct a arbitrary: b) - apply (simp add: list_rel_empty) - apply (case_tac b) - apply simp_all - done - (* induct_tac doesn't accept 'arbitrary', so we manually 'spec' *) lemma foldl_rsp[quot_respect]: assumes q1: "Quotient R1 Abs1 Rep1" and q2: "Quotient R2 Abs2 Rep2" - shows "((R1 ===> R2 ===> R1) ===> R1 ===> list_rel R2 ===> R1) foldl foldl" + shows "((R1 ===> R2 ===> R1) ===> R1 ===> list_all2 R2 ===> R1) foldl foldl" apply(auto) - apply (subgoal_tac "R1 xa ya \ list_rel R2 xb yb \ R1 (foldl x xa xb) (foldl y ya yb)") + apply (subgoal_tac "R1 xa ya \ list_all2 R2 xb yb \ R1 (foldl x xa xb) (foldl y ya yb)") apply simp apply (rule_tac x="xa" in spec) apply (rule_tac x="ya" in spec) apply (rule_tac xs="xb" and ys="yb" in list_induct2) - apply (rule list_rel_len) + apply (rule list_all2_lengthD) apply (simp_all) done lemma foldr_rsp[quot_respect]: assumes q1: "Quotient R1 Abs1 Rep1" and q2: "Quotient R2 Abs2 Rep2" - shows "((R1 ===> R2 ===> R2) ===> list_rel R1 ===> R2 ===> R2) foldr foldr" + shows "((R1 ===> R2 ===> R2) ===> list_all2 R1 ===> R2 ===> R2) foldr foldr" apply auto - apply(subgoal_tac "R2 xb yb \ list_rel R1 xa ya \ R2 (foldr x xa xb) (foldr y ya yb)") + apply(subgoal_tac "R2 xb yb \ list_all2 R1 xa ya \ R2 (foldr x xa xb) (foldr y ya yb)") apply simp apply (rule_tac xs="xa" and ys="ya" in list_induct2) - apply (rule list_rel_len) + apply (rule list_all2_lengthD) apply (simp_all) done -lemma list_rel_rsp: +lemma list_all2_rsp: assumes r: "\x y. R x y \ (\a b. R a b \ S x a = T y b)" - and l1: "list_rel R x y" - and l2: "list_rel R a b" - shows "list_rel S x a = list_rel T y b" + and l1: "list_all2 R x y" + and l2: "list_all2 R a b" + shows "list_all2 S x a = list_all2 T y b" proof - - have a: "length y = length x" by (rule list_rel_len[OF l1, symmetric]) - have c: "length a = length b" by (rule list_rel_len[OF l2]) + have a: "length y = length x" by (rule list_all2_lengthD[OF l1, symmetric]) + have c: "length a = length b" by (rule list_all2_lengthD[OF l2]) show ?thesis proof (cases "length x = length a") case True have b: "length x = length a" by fact @@ -243,20 +217,20 @@ next case False have d: "length x \ length a" by fact - then have e: "\list_rel S x a" using list_rel_len by auto + then have e: "\list_all2 S x a" using list_all2_lengthD by auto have "length y \ length b" using d a c by simp - then have "\list_rel T y b" using list_rel_len by auto + then have "\list_all2 T y b" using list_all2_lengthD by auto then show ?thesis using e by simp qed qed lemma[quot_respect]: - "((R ===> R ===> op =) ===> list_rel R ===> list_rel R ===> op =) list_rel list_rel" - by (simp add: list_rel_rsp) + "((R ===> R ===> op =) ===> list_all2 R ===> list_all2 R ===> op =) list_all2 list_all2" + by (simp add: list_all2_rsp) lemma[quot_preserve]: assumes a: "Quotient R abs1 rep1" - shows "((abs1 ---> abs1 ---> id) ---> map rep1 ---> map rep1 ---> id) list_rel = list_rel" + shows "((abs1 ---> abs1 ---> id) ---> map rep1 ---> map rep1 ---> id) list_all2 = list_all2" apply (simp add: expand_fun_eq) apply clarify apply (induct_tac xa xb rule: list_induct2') @@ -265,29 +239,29 @@ lemma[quot_preserve]: assumes a: "Quotient R abs1 rep1" - shows "(list_rel ((rep1 ---> rep1 ---> id) R) l m) = (l = m)" + shows "(list_all2 ((rep1 ---> rep1 ---> id) R) l m) = (l = m)" by (induct l m rule: list_induct2') (simp_all add: Quotient_rel_rep[OF a]) -lemma list_rel_eq[id_simps]: - shows "(list_rel (op =)) = (op =)" +lemma list_all2_eq[id_simps]: + shows "(list_all2 (op =)) = (op =)" unfolding expand_fun_eq apply(rule allI)+ apply(induct_tac x xa rule: list_induct2') apply(simp_all) done -lemma list_rel_find_element: +lemma list_all2_find_element: assumes a: "x \ set a" - and b: "list_rel R a b" + and b: "list_all2 R a b" shows "\y. (y \ set b \ R x y)" proof - - have "length a = length b" using b by (rule list_rel_len) + have "length a = length b" using b by (rule list_all2_lengthD) then show ?thesis using a b by (induct a b rule: list_induct2) auto qed -lemma list_rel_refl: +lemma list_all2_refl: assumes a: "\x y. R x y = (R x = R y)" - shows "list_rel R x x" + shows "list_all2 R x x" by (induct x) (auto simp add: a) end diff -r b5989aa32358 -r ab36b1a50ca8 src/HOL/Quotient_Examples/FSet.thy --- a/src/HOL/Quotient_Examples/FSet.thy Tue Jun 22 19:46:16 2010 +0200 +++ b/src/HOL/Quotient_Examples/FSet.thy Wed Jun 23 08:42:41 2010 +0200 @@ -80,20 +80,20 @@ text {* Composition Quotient *} -lemma list_rel_refl: - shows "(list_rel op \) r r" - by (rule list_rel_refl) (metis equivp_def fset_equivp) +lemma list_all2_refl: + shows "(list_all2 op \) r r" + by (rule list_all2_refl) (metis equivp_def fset_equivp) lemma compose_list_refl: - shows "(list_rel op \ OOO op \) r r" + shows "(list_all2 op \ OOO op \) r r" proof have *: "r \ r" by (rule equivp_reflp[OF fset_equivp]) - show "list_rel op \ r r" by (rule list_rel_refl) - with * show "(op \ OO list_rel op \) r r" .. + show "list_all2 op \ r r" by (rule list_all2_refl) + with * show "(op \ OO list_all2 op \) r r" .. qed lemma Quotient_fset_list: - shows "Quotient (list_rel op \) (map abs_fset) (map rep_fset)" + shows "Quotient (list_all2 op \) (map abs_fset) (map rep_fset)" by (fact list_quotient[OF Quotient_fset]) lemma set_in_eq: "(\e. ((e \ xs) \ (e \ ys))) \ xs = ys" @@ -104,32 +104,32 @@ by (simp only: set_map set_in_eq) lemma quotient_compose_list[quot_thm]: - shows "Quotient ((list_rel op \) OOO (op \)) + shows "Quotient ((list_all2 op \) OOO (op \)) (abs_fset \ (map abs_fset)) ((map rep_fset) \ rep_fset)" unfolding Quotient_def comp_def proof (intro conjI allI) fix a r s show "abs_fset (map abs_fset (map rep_fset (rep_fset a))) = a" by (simp add: abs_o_rep[OF Quotient_fset] Quotient_abs_rep[OF Quotient_fset] map_id) - have b: "list_rel op \ (map rep_fset (rep_fset a)) (map rep_fset (rep_fset a))" - by (rule list_rel_refl) - have c: "(op \ OO list_rel op \) (map rep_fset (rep_fset a)) (map rep_fset (rep_fset a))" + have b: "list_all2 op \ (map rep_fset (rep_fset a)) (map rep_fset (rep_fset a))" + by (rule list_all2_refl) + have c: "(op \ OO list_all2 op \) (map rep_fset (rep_fset a)) (map rep_fset (rep_fset a))" by (rule, rule equivp_reflp[OF fset_equivp]) (rule b) - show "(list_rel op \ OOO op \) (map rep_fset (rep_fset a)) (map rep_fset (rep_fset a))" - by (rule, rule list_rel_refl) (rule c) - show "(list_rel op \ OOO op \) r s = ((list_rel op \ OOO op \) r r \ - (list_rel op \ OOO op \) s s \ abs_fset (map abs_fset r) = abs_fset (map abs_fset s))" + show "(list_all2 op \ OOO op \) (map rep_fset (rep_fset a)) (map rep_fset (rep_fset a))" + by (rule, rule list_all2_refl) (rule c) + show "(list_all2 op \ OOO op \) r s = ((list_all2 op \ OOO op \) r r \ + (list_all2 op \ OOO op \) s s \ abs_fset (map abs_fset r) = abs_fset (map abs_fset s))" proof (intro iffI conjI) - show "(list_rel op \ OOO op \) r r" by (rule compose_list_refl) - show "(list_rel op \ OOO op \) s s" by (rule compose_list_refl) + show "(list_all2 op \ OOO op \) r r" by (rule compose_list_refl) + show "(list_all2 op \ OOO op \) s s" by (rule compose_list_refl) next - assume a: "(list_rel op \ OOO op \) r s" + assume a: "(list_all2 op \ OOO op \) r s" then have b: "map abs_fset r \ map abs_fset s" proof (elim pred_compE) fix b ba - assume c: "list_rel op \ r b" + assume c: "list_all2 op \ r b" assume d: "b \ ba" - assume e: "list_rel op \ ba s" + assume e: "list_all2 op \ ba s" have f: "map abs_fset r = map abs_fset b" using Quotient_rel[OF Quotient_fset_list] c by blast have "map abs_fset ba = map abs_fset s" @@ -140,20 +140,20 @@ then show "abs_fset (map abs_fset r) = abs_fset (map abs_fset s)" using Quotient_rel[OF Quotient_fset] by blast next - assume a: "(list_rel op \ OOO op \) r r \ (list_rel op \ OOO op \) s s + assume a: "(list_all2 op \ OOO op \) r r \ (list_all2 op \ OOO op \) s s \ abs_fset (map abs_fset r) = abs_fset (map abs_fset s)" - then have s: "(list_rel op \ OOO op \) s s" by simp + then have s: "(list_all2 op \ OOO op \) s s" by simp have d: "map abs_fset r \ map abs_fset s" by (subst Quotient_rel[OF Quotient_fset]) (simp add: a) have b: "map rep_fset (map abs_fset r) \ map rep_fset (map abs_fset s)" by (rule map_rel_cong[OF d]) - have y: "list_rel op \ (map rep_fset (map abs_fset s)) s" - by (fact rep_abs_rsp_left[OF Quotient_fset_list, OF list_rel_refl[of s]]) - have c: "(op \ OO list_rel op \) (map rep_fset (map abs_fset r)) s" + have y: "list_all2 op \ (map rep_fset (map abs_fset s)) s" + by (fact rep_abs_rsp_left[OF Quotient_fset_list, OF list_all2_refl[of s]]) + have c: "(op \ OO list_all2 op \) (map rep_fset (map abs_fset r)) s" by (rule pred_compI) (rule b, rule y) - have z: "list_rel op \ r (map rep_fset (map abs_fset r))" - by (fact rep_abs_rsp[OF Quotient_fset_list, OF list_rel_refl[of r]]) - then show "(list_rel op \ OOO op \) r s" + have z: "list_all2 op \ r (map rep_fset (map abs_fset r))" + by (fact rep_abs_rsp[OF Quotient_fset_list, OF list_all2_refl[of r]]) + then show "(list_all2 op \ OOO op \) r s" using a c pred_compI by simp qed qed @@ -336,27 +336,27 @@ by (simp add: memb_def[symmetric] ffold_raw_rsp_pre) lemma concat_rsp_pre: - assumes a: "list_rel op \ x x'" + assumes a: "list_all2 op \ x x'" and b: "x' \ y'" - and c: "list_rel op \ y' y" + and c: "list_all2 op \ y' y" and d: "\x\set x. xa \ set x" shows "\x\set y. xa \ set x" proof - obtain xb where e: "xb \ set x" and f: "xa \ set xb" using d by auto - have "\y. y \ set x' \ xb \ y" by (rule list_rel_find_element[OF e a]) + have "\y. y \ set x' \ xb \ y" by (rule list_all2_find_element[OF e a]) then obtain ya where h: "ya \ set x'" and i: "xb \ ya" by auto have "ya \ set y'" using b h by simp - then have "\yb. yb \ set y \ ya \ yb" using c by (rule list_rel_find_element) + then have "\yb. yb \ set y \ ya \ yb" using c by (rule list_all2_find_element) then show ?thesis using f i by auto qed lemma [quot_respect]: - shows "(list_rel op \ OOO op \ ===> op \) concat concat" + shows "(list_all2 op \ OOO op \ ===> op \) concat concat" proof (rule fun_relI, elim pred_compE) fix a b ba bb - assume a: "list_rel op \ a ba" + assume a: "list_all2 op \ a ba" assume b: "ba \ bb" - assume c: "list_rel op \ bb b" + assume c: "list_all2 op \ bb b" have "\x. (\xa\set a. x \ set xa) = (\xa\set b. x \ set xa)" proof fix x show "(\xa\set a. x \ set xa) = (\xa\set b. x \ set xa)" proof @@ -364,9 +364,9 @@ show "\xa\set b. x \ set xa" by (rule concat_rsp_pre[OF a b c d]) next assume e: "\xa\set b. x \ set xa" - have a': "list_rel op \ ba a" by (rule list_rel_symp[OF list_eq_equivp, OF a]) + have a': "list_all2 op \ ba a" by (rule list_all2_symp[OF list_eq_equivp, OF a]) have b': "bb \ ba" by (rule equivp_symp[OF list_eq_equivp, OF b]) - have c': "list_rel op \ b bb" by (rule list_rel_symp[OF list_eq_equivp, OF c]) + have c': "list_all2 op \ b bb" by (rule list_all2_symp[OF list_eq_equivp, OF c]) show "\xa\set a. x \ set xa" by (rule concat_rsp_pre[OF c' b' a' e]) qed qed @@ -581,14 +581,14 @@ text {* Compositional Respectfullness and Preservation *} -lemma [quot_respect]: "(list_rel op \ OOO op \) [] []" +lemma [quot_respect]: "(list_all2 op \ OOO op \) [] []" by (fact compose_list_refl) lemma [quot_preserve]: "(abs_fset \ map f) [] = abs_fset []" by simp lemma [quot_respect]: - "(op \ ===> list_rel op \ OOO op \ ===> list_rel op \ OOO op \) op # op #" + "(op \ ===> list_all2 op \ OOO op \ ===> list_all2 op \ OOO op \) op # op #" apply auto apply (simp add: set_in_eq) apply (rule_tac b="x # b" in pred_compI) @@ -607,59 +607,59 @@ by (simp add: expand_fun_eq Quotient_abs_rep[OF Quotient_fset] abs_o_rep[OF Quotient_fset] map_id sup_fset_def) -lemma list_rel_app_l: +lemma list_all2_app_l: assumes a: "reflp R" - and b: "list_rel R l r" - shows "list_rel R (z @ l) (z @ r)" + and b: "list_all2 R l r" + shows "list_all2 R (z @ l) (z @ r)" by (induct z) (simp_all add: b rev_iffD1[OF a meta_eq_to_obj_eq[OF reflp_def]]) lemma append_rsp2_pre0: - assumes a:"list_rel op \ x x'" - shows "list_rel op \ (x @ z) (x' @ z)" + assumes a:"list_all2 op \ x x'" + shows "list_all2 op \ (x @ z) (x' @ z)" using a apply (induct x x' rule: list_induct2') - by simp_all (rule list_rel_refl) + by simp_all (rule list_all2_refl) lemma append_rsp2_pre1: - assumes a:"list_rel op \ x x'" - shows "list_rel op \ (z @ x) (z @ x')" + assumes a:"list_all2 op \ x x'" + shows "list_all2 op \ (z @ x) (z @ x')" using a apply (induct x x' arbitrary: z rule: list_induct2') - apply (rule list_rel_refl) + apply (rule list_all2_refl) apply (simp_all del: list_eq.simps) - apply (rule list_rel_app_l) + apply (rule list_all2_app_l) apply (simp_all add: reflp_def) done lemma append_rsp2_pre: - assumes a:"list_rel op \ x x'" - and b: "list_rel op \ z z'" - shows "list_rel op \ (x @ z) (x' @ z')" - apply (rule list_rel_transp[OF fset_equivp]) + assumes a:"list_all2 op \ x x'" + and b: "list_all2 op \ z z'" + shows "list_all2 op \ (x @ z) (x' @ z')" + apply (rule list_all2_transp[OF fset_equivp]) apply (rule append_rsp2_pre0) apply (rule a) using b apply (induct z z' rule: list_induct2') apply (simp_all only: append_Nil2) - apply (rule list_rel_refl) + apply (rule list_all2_refl) apply simp_all apply (rule append_rsp2_pre1) apply simp done lemma [quot_respect]: - "(list_rel op \ OOO op \ ===> list_rel op \ OOO op \ ===> list_rel op \ OOO op \) op @ op @" + "(list_all2 op \ OOO op \ ===> list_all2 op \ OOO op \ ===> list_all2 op \ OOO op \) op @ op @" proof (intro fun_relI, elim pred_compE) fix x y z w x' z' y' w' :: "'a list list" - assume a:"list_rel op \ x x'" + assume a:"list_all2 op \ x x'" and b: "x' \ y'" - and c: "list_rel op \ y' y" - assume aa: "list_rel op \ z z'" + and c: "list_all2 op \ y' y" + assume aa: "list_all2 op \ z z'" and bb: "z' \ w'" - and cc: "list_rel op \ w' w" - have a': "list_rel op \ (x @ z) (x' @ z')" using a aa append_rsp2_pre by auto + and cc: "list_all2 op \ w' w" + have a': "list_all2 op \ (x @ z) (x' @ z')" using a aa append_rsp2_pre by auto have b': "x' @ z' \ y' @ w'" using b bb by simp - have c': "list_rel op \ (y' @ w') (y @ w)" using c cc append_rsp2_pre by auto - have d': "(op \ OO list_rel op \) (x' @ z') (y @ w)" + have c': "list_all2 op \ (y' @ w') (y @ w)" using c cc append_rsp2_pre by auto + have d': "(op \ OO list_all2 op \) (x' @ z') (y @ w)" by (rule pred_compI) (rule b', rule c') - show "(list_rel op \ OOO op \) (x @ z) (y @ w)" + show "(list_all2 op \ OOO op \) (x @ z) (y @ w)" by (rule pred_compI) (rule a', rule d') qed