diff -r 243a5ceaa088 -r 17ca92ab4660 Quot/Quotient.thy
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Quot/Quotient.thy	Thu Feb 11 10:06:02 2010 +0100
@@ -0,0 +1,802 @@
+(*  Title:      QuotMain.thy
+    Author:     Cezary Kaliszyk and Christian Urban
+*)
+
+theory Quotient
+imports Plain ATP_Linkup
+uses
+  ("quotient_info.ML")
+  ("quotient_typ.ML")
+  ("quotient_def.ML")
+  ("quotient_term.ML")
+  ("quotient_tacs.ML")
+begin
+
+text {*
+  Basic definition for equivalence relations
+  that are represented by predicates.
+*}
+
+definition
+  "equivp E \<longleftrightarrow> (\<forall>x y. E x y = (E x = E y))"
+
+definition
+  "reflp E \<longleftrightarrow> (\<forall>x. E x x)"
+
+definition
+  "symp E \<longleftrightarrow> (\<forall>x y. E x y \<longrightarrow> E y x)"
+
+definition
+  "transp E \<longleftrightarrow> (\<forall>x y z. E x y \<and> E y z \<longrightarrow> E x z)"
+
+lemma equivp_reflp_symp_transp:
+  shows "equivp E = (reflp E \<and> symp E \<and> transp E)"
+  unfolding equivp_def reflp_def symp_def transp_def expand_fun_eq
+  by blast
+
+lemma equivp_reflp:
+  shows "equivp E \<Longrightarrow> E x x"
+  by (simp only: equivp_reflp_symp_transp reflp_def)
+
+lemma equivp_symp:
+  shows "equivp E \<Longrightarrow> E x y \<Longrightarrow> E y x"
+  by (metis equivp_reflp_symp_transp symp_def)
+
+lemma equivp_transp:
+  shows "equivp E \<Longrightarrow> E x y \<Longrightarrow> E y z \<Longrightarrow> E x z"
+  by (metis equivp_reflp_symp_transp transp_def)
+
+lemma equivpI:
+  assumes "reflp R" "symp R" "transp R"
+  shows "equivp R"
+  using assms by (simp add: equivp_reflp_symp_transp)
+
+lemma eq_imp_rel:
+  shows "equivp R \<Longrightarrow> a = b \<longrightarrow> R a b"
+  by (simp add: equivp_reflp)
+
+lemma identity_equivp:
+  shows "equivp (op =)"
+  unfolding equivp_def
+  by auto
+
+
+text {* Partial equivalences: not yet used anywhere *}
+definition
+  "part_equivp E \<longleftrightarrow> ((\<exists>x. E x x) \<and> (\<forall>x y. E x y = (E x x \<and> E y y \<and> (E x = E y))))"
+
+lemma equivp_implies_part_equivp:
+  assumes a: "equivp E"
+  shows "part_equivp E"
+  using a
+  unfolding equivp_def part_equivp_def
+  by auto
+
+text {* Composition of Relations *}
+
+abbreviation
+  rel_conj (infixr "OOO" 75)
+where
+  "r1 OOO r2 \<equiv> r1 OO r2 OO r1"
+
+lemma eq_comp_r:
+  shows "((op =) OOO R) = R"
+  by (auto simp add: expand_fun_eq)
+
+section {* Respects predicate *}
+
+definition
+  Respects
+where
+  "Respects R x \<longleftrightarrow> (R x x)"
+
+lemma in_respects:
+  shows "(x \<in> Respects R) = R x x"
+  unfolding mem_def Respects_def
+  by simp
+
+section {* Function map and function relation *}
+
+definition
+  fun_map (infixr "--->" 55)
+where
+[simp]: "fun_map f g h x = g (h (f x))"
+
+definition
+  fun_rel (infixr "===>" 55)
+where
+[simp]: "fun_rel E1 E2 f g = (\<forall>x y. E1 x y \<longrightarrow> E2 (f x) (g y))"
+
+
+lemma fun_map_id:
+  shows "(id ---> id) = id"
+  by (simp add: expand_fun_eq id_def)
+
+lemma fun_rel_eq:
+  shows "((op =) ===> (op =)) = (op =)"
+  by (simp add: expand_fun_eq)
+
+lemma fun_rel_id:
+  assumes a: "\<And>x y. R1 x y \<Longrightarrow> R2 (f x) (g y)"
+  shows "(R1 ===> R2) f g"
+  using a by simp
+
+lemma fun_rel_id_asm:
+  assumes a: "\<And>x y. R1 x y \<Longrightarrow> (A \<longrightarrow> R2 (f x) (g y))"
+  shows "A \<longrightarrow> (R1 ===> R2) f g"
+  using a by auto
+
+
+section {* Quotient Predicate *}
+
+definition
+  "Quotient E Abs Rep \<longleftrightarrow>
+     (\<forall>a. Abs (Rep a) = a) \<and> (\<forall>a. E (Rep a) (Rep a)) \<and>
+     (\<forall>r s. E r s = (E r r \<and> E s s \<and> (Abs r = Abs s)))"
+
+lemma Quotient_abs_rep:
+  assumes a: "Quotient E Abs Rep"
+  shows "Abs (Rep a) = a"
+  using a
+  unfolding Quotient_def
+  by simp
+
+lemma Quotient_rep_reflp:
+  assumes a: "Quotient E Abs Rep"
+  shows "E (Rep a) (Rep a)"
+  using a
+  unfolding Quotient_def
+  by blast
+
+lemma Quotient_rel:
+  assumes a: "Quotient E Abs Rep"
+  shows " E r s = (E r r \<and> E s s \<and> (Abs r = Abs s))"
+  using a
+  unfolding Quotient_def
+  by blast
+
+lemma Quotient_rel_rep:
+  assumes a: "Quotient R Abs Rep"
+  shows "R (Rep a) (Rep b) = (a = b)"
+  using a
+  unfolding Quotient_def
+  by metis
+
+lemma Quotient_rep_abs:
+  assumes a: "Quotient R Abs Rep"
+  shows "R r r \<Longrightarrow> R (Rep (Abs r)) r"
+  using a unfolding Quotient_def
+  by blast
+
+lemma Quotient_rel_abs:
+  assumes a: "Quotient E Abs Rep"
+  shows "E r s \<Longrightarrow> Abs r = Abs s"
+  using a unfolding Quotient_def
+  by blast
+
+lemma Quotient_symp:
+  assumes a: "Quotient E Abs Rep"
+  shows "symp E"
+  using a unfolding Quotient_def symp_def
+  by metis
+
+lemma Quotient_transp:
+  assumes a: "Quotient E Abs Rep"
+  shows "transp E"
+  using a unfolding Quotient_def transp_def
+  by metis
+
+lemma identity_quotient:
+  shows "Quotient (op =) id id"
+  unfolding Quotient_def id_def
+  by blast
+
+lemma fun_quotient:
+  assumes q1: "Quotient R1 abs1 rep1"
+  and     q2: "Quotient R2 abs2 rep2"
+  shows "Quotient (R1 ===> R2) (rep1 ---> abs2) (abs1 ---> rep2)"
+proof -
+  have "\<forall>a. (rep1 ---> abs2) ((abs1 ---> rep2) a) = a"
+    using q1 q2
+    unfolding Quotient_def
+    unfolding expand_fun_eq
+    by simp
+  moreover
+  have "\<forall>a. (R1 ===> R2) ((abs1 ---> rep2) a) ((abs1 ---> rep2) a)"
+    using q1 q2
+    unfolding Quotient_def
+    by (simp (no_asm)) (metis)
+  moreover
+  have "\<forall>r s. (R1 ===> R2) r s = ((R1 ===> R2) r r \<and> (R1 ===> R2) s s \<and>
+        (rep1 ---> abs2) r  = (rep1 ---> abs2) s)"
+    unfolding expand_fun_eq
+    apply(auto)
+    using q1 q2 unfolding Quotient_def
+    apply(metis)
+    using q1 q2 unfolding Quotient_def
+    apply(metis)
+    using q1 q2 unfolding Quotient_def
+    apply(metis)
+    using q1 q2 unfolding Quotient_def
+    apply(metis)
+    done
+  ultimately
+  show "Quotient (R1 ===> R2) (rep1 ---> abs2) (abs1 ---> rep2)"
+    unfolding Quotient_def by blast
+qed
+
+lemma abs_o_rep:
+  assumes a: "Quotient R Abs Rep"
+  shows "Abs o Rep = id"
+  unfolding expand_fun_eq
+  by (simp add: Quotient_abs_rep[OF a])
+
+lemma equals_rsp:
+  assumes q: "Quotient R Abs Rep"
+  and     a: "R xa xb" "R ya yb"
+  shows "R xa ya = R xb yb"
+  using a Quotient_symp[OF q] Quotient_transp[OF q]
+  unfolding symp_def transp_def
+  by blast
+
+lemma lambda_prs:
+  assumes q1: "Quotient R1 Abs1 Rep1"
+  and     q2: "Quotient R2 Abs2 Rep2"
+  shows "(Rep1 ---> Abs2) (\<lambda>x. Rep2 (f (Abs1 x))) = (\<lambda>x. f x)"
+  unfolding expand_fun_eq
+  using Quotient_abs_rep[OF q1] Quotient_abs_rep[OF q2]
+  by simp
+
+lemma lambda_prs1:
+  assumes q1: "Quotient R1 Abs1 Rep1"
+  and     q2: "Quotient R2 Abs2 Rep2"
+  shows "(Rep1 ---> Abs2) (\<lambda>x. (Abs1 ---> Rep2) f x) = (\<lambda>x. f x)"
+  unfolding expand_fun_eq
+  using Quotient_abs_rep[OF q1] Quotient_abs_rep[OF q2]
+  by simp
+
+lemma rep_abs_rsp:
+  assumes q: "Quotient R Abs Rep"
+  and     a: "R x1 x2"
+  shows "R x1 (Rep (Abs x2))"
+  using a Quotient_rel[OF q] Quotient_abs_rep[OF q] Quotient_rep_reflp[OF q]
+  by metis
+
+lemma rep_abs_rsp_left:
+  assumes q: "Quotient R Abs Rep"
+  and     a: "R x1 x2"
+  shows "R (Rep (Abs x1)) x2"
+  using a Quotient_rel[OF q] Quotient_abs_rep[OF q] Quotient_rep_reflp[OF q]
+  by metis
+
+text{*
+  In the following theorem R1 can be instantiated with anything,
+  but we know some of the types of the Rep and Abs functions;
+  so by solving Quotient assumptions we can get a unique R1 that
+  will be provable; which is why we need to use apply_rsp and
+  not the primed version *}
+
+lemma apply_rsp:
+  fixes f g::"'a \<Rightarrow> 'c"
+  assumes q: "Quotient R1 Abs1 Rep1"
+  and     a: "(R1 ===> R2) f g" "R1 x y"
+  shows "R2 (f x) (g y)"
+  using a by simp
+
+lemma apply_rsp':
+  assumes a: "(R1 ===> R2) f g" "R1 x y"
+  shows "R2 (f x) (g y)"
+  using a by simp
+
+section {* lemmas for regularisation of ball and bex *}
+
+lemma ball_reg_eqv:
+  fixes P :: "'a \<Rightarrow> bool"
+  assumes a: "equivp R"
+  shows "Ball (Respects R) P = (All P)"
+  using a
+  unfolding equivp_def
+  by (auto simp add: in_respects)
+
+lemma bex_reg_eqv:
+  fixes P :: "'a \<Rightarrow> bool"
+  assumes a: "equivp R"
+  shows "Bex (Respects R) P = (Ex P)"
+  using a
+  unfolding equivp_def
+  by (auto simp add: in_respects)
+
+lemma ball_reg_right:
+  assumes a: "\<And>x. R x \<Longrightarrow> P x \<longrightarrow> Q x"
+  shows "All P \<longrightarrow> Ball R Q"
+  using a by (metis COMBC_def Collect_def Collect_mem_eq)
+
+lemma bex_reg_left:
+  assumes a: "\<And>x. R x \<Longrightarrow> Q x \<longrightarrow> P x"
+  shows "Bex R Q \<longrightarrow> Ex P"
+  using a by (metis COMBC_def Collect_def Collect_mem_eq)
+
+lemma ball_reg_left:
+  assumes a: "equivp R"
+  shows "(\<And>x. (Q x \<longrightarrow> P x)) \<Longrightarrow> Ball (Respects R) Q \<longrightarrow> All P"
+  using a by (metis equivp_reflp in_respects)
+
+lemma bex_reg_right:
+  assumes a: "equivp R"
+  shows "(\<And>x. (Q x \<longrightarrow> P x)) \<Longrightarrow> Ex Q \<longrightarrow> Bex (Respects R) P"
+  using a by (metis equivp_reflp in_respects)
+
+lemma ball_reg_eqv_range:
+  fixes P::"'a \<Rightarrow> bool"
+  and x::"'a"
+  assumes a: "equivp R2"
+  shows   "(Ball (Respects (R1 ===> R2)) (\<lambda>f. P (f x)) = All (\<lambda>f. P (f x)))"
+  apply(rule iffI)
+  apply(rule allI)
+  apply(drule_tac x="\<lambda>y. f x" in bspec)
+  apply(simp add: in_respects)
+  apply(rule impI)
+  using a equivp_reflp_symp_transp[of "R2"]
+  apply(simp add: reflp_def)
+  apply(simp)
+  apply(simp)
+  done
+
+lemma bex_reg_eqv_range:
+  assumes a: "equivp R2"
+  shows   "(Bex (Respects (R1 ===> R2)) (\<lambda>f. P (f x)) = Ex (\<lambda>f. P (f x)))"
+  apply(auto)
+  apply(rule_tac x="\<lambda>y. f x" in bexI)
+  apply(simp)
+  apply(simp add: Respects_def in_respects)
+  apply(rule impI)
+  using a equivp_reflp_symp_transp[of "R2"]
+  apply(simp add: reflp_def)
+  done
+
+lemma all_reg:
+  assumes a: "!x :: 'a. (P x --> Q x)"
+  and     b: "All P"
+  shows "All Q"
+  using a b by (metis)
+
+lemma ex_reg:
+  assumes a: "!x :: 'a. (P x --> Q x)"
+  and     b: "Ex P"
+  shows "Ex Q"
+  using a b by metis
+
+lemma ball_reg:
+  assumes a: "!x :: 'a. (R x --> P x --> Q x)"
+  and     b: "Ball R P"
+  shows "Ball R Q"
+  using a b by (metis COMBC_def Collect_def Collect_mem_eq)
+
+lemma bex_reg:
+  assumes a: "!x :: 'a. (R x --> P x --> Q x)"
+  and     b: "Bex R P"
+  shows "Bex R Q"
+  using a b by (metis COMBC_def Collect_def Collect_mem_eq)
+
+lemma ball_all_comm:
+  assumes "\<And>y. (\<forall>x\<in>P. A x y) \<longrightarrow> (\<forall>x. B x y)"
+  shows "(\<forall>x\<in>P. \<forall>y. A x y) \<longrightarrow> (\<forall>x. \<forall>y. B x y)"
+  using assms by auto
+
+lemma bex_ex_comm:
+  assumes "(\<exists>y. \<exists>x. A x y) \<longrightarrow> (\<exists>y. \<exists>x\<in>P. B x y)"
+  shows "(\<exists>x. \<exists>y. A x y) \<longrightarrow> (\<exists>x\<in>P. \<exists>y. B x y)"
+  using assms by auto
+
+section {* Bounded abstraction *}
+
+definition
+  Babs :: "('a \<Rightarrow> bool) \<Rightarrow> ('a \<Rightarrow> 'b) \<Rightarrow> 'a \<Rightarrow> 'b"
+where
+  "x \<in> p \<Longrightarrow> Babs p m x = m x"
+
+lemma babs_rsp:
+  assumes q: "Quotient R1 Abs1 Rep1"
+  and     a: "(R1 ===> R2) f g"
+  shows      "(R1 ===> R2) (Babs (Respects R1) f) (Babs (Respects R1) g)"
+  apply (auto simp add: Babs_def in_respects)
+  apply (subgoal_tac "x \<in> Respects R1 \<and> y \<in> Respects R1")
+  using a apply (simp add: Babs_def)
+  apply (simp add: in_respects)
+  using Quotient_rel[OF q]
+  by metis
+
+lemma babs_prs:
+  assumes q1: "Quotient R1 Abs1 Rep1"
+  and     q2: "Quotient R2 Abs2 Rep2"
+  shows "((Rep1 ---> Abs2) (Babs (Respects R1) ((Abs1 ---> Rep2) f))) = f"
+  apply (rule ext)
+  apply (simp)
+  apply (subgoal_tac "Rep1 x \<in> Respects R1")
+  apply (simp add: Babs_def Quotient_abs_rep[OF q1] Quotient_abs_rep[OF q2])
+  apply (simp add: in_respects Quotient_rel_rep[OF q1])
+  done
+
+lemma babs_simp:
+  assumes q: "Quotient R1 Abs Rep"
+  shows "((R1 ===> R2) (Babs (Respects R1) f) (Babs (Respects R1) g)) = ((R1 ===> R2) f g)"
+  apply(rule iffI)
+  apply(simp_all only: babs_rsp[OF q])
+  apply(auto simp add: Babs_def)
+  apply (subgoal_tac "x \<in> Respects R1 \<and> y \<in> Respects R1")
+  apply(metis Babs_def)
+  apply (simp add: in_respects)
+  using Quotient_rel[OF q]
+  by metis
+
+(* If a user proves that a particular functional relation
+   is an equivalence this may be useful in regularising *)
+lemma babs_reg_eqv:
+  shows "equivp R \<Longrightarrow> Babs (Respects R) P = P"
+  by (simp add: expand_fun_eq Babs_def in_respects equivp_reflp)
+
+
+(* 3 lemmas needed for proving repabs_inj *)
+lemma ball_rsp:
+  assumes a: "(R ===> (op =)) f g"
+  shows "Ball (Respects R) f = Ball (Respects R) g"
+  using a by (simp add: Ball_def in_respects)
+
+lemma bex_rsp:
+  assumes a: "(R ===> (op =)) f g"
+  shows "(Bex (Respects R) f = Bex (Respects R) g)"
+  using a by (simp add: Bex_def in_respects)
+
+lemma bex1_rsp:
+  assumes a: "(R ===> (op =)) f g"
+  shows "Ex1 (\<lambda>x. x \<in> Respects R \<and> f x) = Ex1 (\<lambda>x. x \<in> Respects R \<and> g x)"
+  using a
+  by (simp add: Ex1_def in_respects) auto
+
+(* 2 lemmas needed for cleaning of quantifiers *)
+lemma all_prs:
+  assumes a: "Quotient R absf repf"
+  shows "Ball (Respects R) ((absf ---> id) f) = All f"
+  using a unfolding Quotient_def Ball_def in_respects fun_map_def id_apply
+  by metis
+
+lemma ex_prs:
+  assumes a: "Quotient R absf repf"
+  shows "Bex (Respects R) ((absf ---> id) f) = Ex f"
+  using a unfolding Quotient_def Bex_def in_respects fun_map_def id_apply
+  by metis
+
+section {* Bex1_rel quantifier *}
+
+definition
+  Bex1_rel :: "('a \<Rightarrow> 'a \<Rightarrow> bool) \<Rightarrow> ('a \<Rightarrow> bool) \<Rightarrow> bool"
+where
+  "Bex1_rel R P \<longleftrightarrow> (\<exists>x \<in> Respects R. P x) \<and> (\<forall>x \<in> Respects R. \<forall>y \<in> Respects R. ((P x \<and> P y) \<longrightarrow> (R x y)))"
+
+lemma bex1_rel_aux:
+  "\<lbrakk>\<forall>xa ya. R xa ya \<longrightarrow> x xa = y ya; Bex1_rel R x\<rbrakk> \<Longrightarrow> Bex1_rel R y"
+  unfolding Bex1_rel_def
+  apply (erule conjE)+
+  apply (erule bexE)
+  apply rule
+  apply (rule_tac x="xa" in bexI)
+  apply metis
+  apply metis
+  apply rule+
+  apply (erule_tac x="xaa" in ballE)
+  prefer 2
+  apply (metis)
+  apply (erule_tac x="ya" in ballE)
+  prefer 2
+  apply (metis)
+  apply (metis in_respects)
+  done
+
+lemma bex1_rel_aux2:
+  "\<lbrakk>\<forall>xa ya. R xa ya \<longrightarrow> x xa = y ya; Bex1_rel R y\<rbrakk> \<Longrightarrow> Bex1_rel R x"
+  unfolding Bex1_rel_def
+  apply (erule conjE)+
+  apply (erule bexE)
+  apply rule
+  apply (rule_tac x="xa" in bexI)
+  apply metis
+  apply metis
+  apply rule+
+  apply (erule_tac x="xaa" in ballE)
+  prefer 2
+  apply (metis)
+  apply (erule_tac x="ya" in ballE)
+  prefer 2
+  apply (metis)
+  apply (metis in_respects)
+  done
+
+lemma bex1_rel_rsp:
+  assumes a: "Quotient R absf repf"
+  shows "((R ===> op =) ===> op =) (Bex1_rel R) (Bex1_rel R)"
+  apply simp
+  apply clarify
+  apply rule
+  apply (simp_all add: bex1_rel_aux bex1_rel_aux2)
+  apply (erule bex1_rel_aux2)
+  apply assumption
+  done
+
+
+lemma ex1_prs:
+  assumes a: "Quotient R absf repf"
+  shows "((absf ---> id) ---> id) (Bex1_rel R) f = Ex1 f"
+apply simp
+apply (subst Bex1_rel_def)
+apply (subst Bex_def)
+apply (subst Ex1_def)
+apply simp
+apply rule
+ apply (erule conjE)+
+ apply (erule_tac exE)
+ apply (erule conjE)
+ apply (subgoal_tac "\<forall>y. R y y \<longrightarrow> f (absf y) \<longrightarrow> R x y")
+  apply (rule_tac x="absf x" in exI)
+  apply (simp)
+  apply rule+
+  using a unfolding Quotient_def
+  apply metis
+ apply rule+
+ apply (erule_tac x="x" in ballE)
+  apply (erule_tac x="y" in ballE)
+   apply simp
+  apply (simp add: in_respects)
+ apply (simp add: in_respects)
+apply (erule_tac exE)
+ apply rule
+ apply (rule_tac x="repf x" in exI)
+ apply (simp only: in_respects)
+  apply rule
+ apply (metis Quotient_rel_rep[OF a])
+using a unfolding Quotient_def apply (simp)
+apply rule+
+using a unfolding Quotient_def in_respects
+apply metis
+done
+
+lemma bex1_bexeq_reg: "(\<exists>!x\<in>Respects R. P x) \<longrightarrow> (Bex1_rel R (\<lambda>x. P x))"
+  apply (simp add: Ex1_def Bex1_rel_def in_respects)
+  apply clarify
+  apply auto
+  apply (rule bexI)
+  apply assumption
+  apply (simp add: in_respects)
+  apply (simp add: in_respects)
+  apply auto
+  done
+
+section {* Various respects and preserve lemmas *}
+
+lemma quot_rel_rsp:
+  assumes a: "Quotient R Abs Rep"
+  shows "(R ===> R ===> op =) R R"
+  apply(rule fun_rel_id)+
+  apply(rule equals_rsp[OF a])
+  apply(assumption)+
+  done
+
+lemma o_prs:
+  assumes q1: "Quotient R1 Abs1 Rep1"
+  and     q2: "Quotient R2 Abs2 Rep2"
+  and     q3: "Quotient R3 Abs3 Rep3"
+  shows "(Rep1 ---> Abs3) (((Abs2 ---> Rep3) f) o ((Abs1 ---> Rep2) g)) = f o g"
+  using Quotient_abs_rep[OF q1] Quotient_abs_rep[OF q2] Quotient_abs_rep[OF q3]
+  unfolding o_def expand_fun_eq by simp
+
+lemma o_rsp:
+  assumes q1: "Quotient R1 Abs1 Rep1"
+  and     q2: "Quotient R2 Abs2 Rep2"
+  and     q3: "Quotient R3 Abs3 Rep3"
+  and     a1: "(R2 ===> R3) f1 f2"
+  and     a2: "(R1 ===> R2) g1 g2"
+  shows "(R1 ===> R3) (f1 o g1) (f2 o g2)"
+  using a1 a2 unfolding o_def expand_fun_eq
+  by (auto)
+
+lemma cond_prs:
+  assumes a: "Quotient R absf repf"
+  shows "absf (if a then repf b else repf c) = (if a then b else c)"
+  using a unfolding Quotient_def by auto
+
+lemma if_prs:
+  assumes q: "Quotient R Abs Rep"
+  shows "Abs (If a (Rep b) (Rep c)) = If a b c"
+  using Quotient_abs_rep[OF q] by auto
+
+(* q not used *)
+lemma if_rsp:
+  assumes q: "Quotient R Abs Rep"
+  and     a: "a1 = a2" "R b1 b2" "R c1 c2"
+  shows "R (If a1 b1 c1) (If a2 b2 c2)"
+  using a by auto
+
+lemma let_prs:
+  assumes q1: "Quotient R1 Abs1 Rep1"
+  and     q2: "Quotient R2 Abs2 Rep2"
+  shows "Abs2 (Let (Rep1 x) ((Abs1 ---> Rep2) f)) = Let x f"
+  using Quotient_abs_rep[OF q1] Quotient_abs_rep[OF q2] by auto
+
+lemma let_rsp:
+  assumes q1: "Quotient R1 Abs1 Rep1"
+  and     a1: "(R1 ===> R2) f g"
+  and     a2: "R1 x y"
+  shows "R2 ((Let x f)::'c) ((Let y g)::'c)"
+  using apply_rsp[OF q1 a1] a2 by auto
+
+locale quot_type =
+  fixes R :: "'a \<Rightarrow> 'a \<Rightarrow> bool"
+  and   Abs :: "('a \<Rightarrow> bool) \<Rightarrow> 'b"
+  and   Rep :: "'b \<Rightarrow> ('a \<Rightarrow> bool)"
+  assumes equivp: "equivp R"
+  and     rep_prop: "\<And>y. \<exists>x. Rep y = R x"
+  and     rep_inverse: "\<And>x. Abs (Rep x) = x"
+  and     abs_inverse: "\<And>x. (Rep (Abs (R x))) = (R x)"
+  and     rep_inject: "\<And>x y. (Rep x = Rep y) = (x = y)"
+begin
+
+definition
+  abs::"'a \<Rightarrow> 'b"
+where
+  "abs x \<equiv> Abs (R x)"
+
+definition
+  rep::"'b \<Rightarrow> 'a"
+where
+  "rep a = Eps (Rep a)"
+
+lemma homeier_lem9:
+  shows "R (Eps (R x)) = R x"
+proof -
+  have a: "R x x" using equivp by (simp add: equivp_reflp_symp_transp reflp_def)
+  then have "R x (Eps (R x))" by (rule someI)
+  then show "R (Eps (R x)) = R x"
+    using equivp unfolding equivp_def by simp
+qed
+
+theorem homeier_thm10:
+  shows "abs (rep a) = a"
+  unfolding abs_def rep_def
+proof -
+  from rep_prop
+  obtain x where eq: "Rep a = R x" by auto
+  have "Abs (R (Eps (Rep a))) = Abs (R (Eps (R x)))" using eq by simp
+  also have "\<dots> = Abs (R x)" using homeier_lem9 by simp
+  also have "\<dots> = Abs (Rep a)" using eq by simp
+  also have "\<dots> = a" using rep_inverse by simp
+  finally
+  show "Abs (R (Eps (Rep a))) = a" by simp
+qed
+
+lemma homeier_lem7:
+  shows "(R x = R y) = (Abs (R x) = Abs (R y))" (is "?LHS = ?RHS")
+proof -
+  have "?RHS = (Rep (Abs (R x)) = Rep (Abs (R y)))" by (simp add: rep_inject)
+  also have "\<dots> = ?LHS" by (simp add: abs_inverse)
+  finally show "?LHS = ?RHS" by simp
+qed
+
+theorem homeier_thm11:
+  shows "R r r' = (abs r = abs r')"
+  unfolding abs_def
+  by (simp only: equivp[simplified equivp_def] homeier_lem7)
+
+lemma rep_refl:
+  shows "R (rep a) (rep a)"
+  unfolding rep_def
+  by (simp add: equivp[simplified equivp_def])
+
+
+lemma rep_abs_rsp:
+  shows "R f (rep (abs g)) = R f g"
+  and   "R (rep (abs g)) f = R g f"
+  by (simp_all add: homeier_thm10 homeier_thm11)
+
+lemma Quotient:
+  shows "Quotient R abs rep"
+  unfolding Quotient_def
+  apply(simp add: homeier_thm10)
+  apply(simp add: rep_refl)
+  apply(subst homeier_thm11[symmetric])
+  apply(simp add: equivp[simplified equivp_def])
+  done
+
+end
+
+section {* ML setup *}
+
+text {* Auxiliary data for the quotient package *}
+
+use "quotient_info.ML"
+
+declare [[map "fun" = (fun_map, fun_rel)]]
+
+lemmas [quot_thm] = fun_quotient
+lemmas [quot_respect] = quot_rel_rsp
+lemmas [quot_equiv] = identity_equivp
+
+
+text {* Lemmas about simplifying id's. *}
+lemmas [id_simps] =
+  id_def[symmetric]
+  fun_map_id
+  id_apply
+  id_o
+  o_id
+  eq_comp_r
+
+text {* Translation functions for the lifting process. *}
+use "quotient_term.ML"
+
+
+text {* Definitions of the quotient types. *}
+use "quotient_typ.ML"
+
+
+text {* Definitions for quotient constants. *}
+use "quotient_def.ML"
+
+
+text {*
+  An auxiliary constant for recording some information
+  about the lifted theorem in a tactic.
+*}
+definition
+  "Quot_True x \<equiv> True"
+
+lemma
+  shows QT_all: "Quot_True (All P) \<Longrightarrow> Quot_True P"
+  and   QT_ex:  "Quot_True (Ex P) \<Longrightarrow> Quot_True P"
+  and   QT_ex1: "Quot_True (Ex1 P) \<Longrightarrow> Quot_True P"
+  and   QT_lam: "Quot_True (\<lambda>x. P x) \<Longrightarrow> (\<And>x. Quot_True (P x))"
+  and   QT_ext: "(\<And>x. Quot_True (a x) \<Longrightarrow> f x = g x) \<Longrightarrow> (Quot_True a \<Longrightarrow> f = g)"
+  by (simp_all add: Quot_True_def ext)
+
+lemma QT_imp: "Quot_True a \<equiv> Quot_True b"
+  by (simp add: Quot_True_def)
+
+
+text {* Tactics for proving the lifted theorems *}
+use "quotient_tacs.ML"
+
+section {* Methods / Interface *}
+
+(* TODO inline *)
+ML {*
+fun mk_method1 tac thms ctxt =
+  SIMPLE_METHOD (HEADGOAL (tac ctxt thms))
+
+fun mk_method2 tac ctxt =
+  SIMPLE_METHOD (HEADGOAL (tac ctxt))
+*}
+
+method_setup lifting =
+  {* Attrib.thms >> (mk_method1 Quotient_Tacs.lift_tac) *}
+  {* lifts theorems to quotient types *}
+
+method_setup lifting_setup =
+  {* Attrib.thm >> (mk_method1 Quotient_Tacs.procedure_tac) *}
+  {* sets up the three goals for the quotient lifting procedure *}
+
+method_setup regularize =
+  {* Scan.succeed (mk_method2 Quotient_Tacs.regularize_tac) *}
+  {* proves the regularization goals from the quotient lifting procedure *}
+
+method_setup injection =
+  {* Scan.succeed (mk_method2 Quotient_Tacs.all_injection_tac) *}
+  {* proves the rep/abs injection goals from the quotient lifting procedure *}
+
+method_setup cleaning =
+  {* Scan.succeed (mk_method2 Quotient_Tacs.clean_tac) *}
+  {* proves the cleaning goals from the quotient lifting procedure *}
+
+attribute_setup quot_lifted =
+  {* Scan.succeed Quotient_Tacs.lifted_attrib *}
+  {* lifts theorems to quotient types *}
+
+end
+