1(*  Title:      HOL/Basic_BNFs.thy
2    Author:     Dmitriy Traytel, TU Muenchen
3    Author:     Andrei Popescu, TU Muenchen
4    Author:     Jasmin Blanchette, TU Muenchen
5    Copyright   2012
6
7Registration of basic types as bounded natural functors.
8*)
9
10section \<open>Registration of Basic Types as Bounded Natural Functors\<close>
11
12theory Basic_BNFs
13imports BNF_Def
14begin
15
16inductive_set setl :: "'a + 'b \<Rightarrow> 'a set" for s :: "'a + 'b" where
17  "s = Inl x \<Longrightarrow> x \<in> setl s"
18inductive_set setr :: "'a + 'b \<Rightarrow> 'b set" for s :: "'a + 'b" where
19  "s = Inr x \<Longrightarrow> x \<in> setr s"
20
21lemma sum_set_defs[code]:
22  "setl = (\<lambda>x. case x of Inl z \<Rightarrow> {z} | _ \<Rightarrow> {})"
23  "setr = (\<lambda>x. case x of Inr z \<Rightarrow> {z} | _ \<Rightarrow> {})"
24  by (auto simp: fun_eq_iff intro: setl.intros setr.intros elim: setl.cases setr.cases split: sum.splits)
25
26lemma rel_sum_simps[code, simp]:
27  "rel_sum R1 R2 (Inl a1) (Inl b1) = R1 a1 b1"
28  "rel_sum R1 R2 (Inl a1) (Inr b2) = False"
29  "rel_sum R1 R2 (Inr a2) (Inl b1) = False"
30  "rel_sum R1 R2 (Inr a2) (Inr b2) = R2 a2 b2"
31  by (auto intro: rel_sum.intros elim: rel_sum.cases)
32
33inductive
34   pred_sum :: "('a \<Rightarrow> bool) \<Rightarrow> ('b \<Rightarrow> bool) \<Rightarrow> 'a + 'b \<Rightarrow> bool" for P1 P2
35where
36  "P1 a \<Longrightarrow> pred_sum P1 P2 (Inl a)"
37| "P2 b \<Longrightarrow> pred_sum P1 P2 (Inr b)"
38
39lemma pred_sum_inject[code, simp]:
40  "pred_sum P1 P2 (Inl a) \<longleftrightarrow> P1 a"
41  "pred_sum P1 P2 (Inr b) \<longleftrightarrow> P2 b"
42  by (simp add: pred_sum.simps)+
43
44bnf "'a + 'b"
45  map: map_sum
46  sets: setl setr
47  bd: natLeq
48  wits: Inl Inr
49  rel: rel_sum
50  pred: pred_sum
51proof -
52  show "map_sum id id = id" by (rule map_sum.id)
53next
54  fix f1 :: "'o \<Rightarrow> 's" and f2 :: "'p \<Rightarrow> 't" and g1 :: "'s \<Rightarrow> 'q" and g2 :: "'t \<Rightarrow> 'r"
55  show "map_sum (g1 \<circ> f1) (g2 \<circ> f2) = map_sum g1 g2 \<circ> map_sum f1 f2"
56    by (rule map_sum.comp[symmetric])
57next
58  fix x and f1 :: "'o \<Rightarrow> 'q" and f2 :: "'p \<Rightarrow> 'r" and g1 g2
59  assume a1: "\<And>z. z \<in> setl x \<Longrightarrow> f1 z = g1 z" and
60         a2: "\<And>z. z \<in> setr x \<Longrightarrow> f2 z = g2 z"
61  thus "map_sum f1 f2 x = map_sum g1 g2 x"
62  proof (cases x)
63    case Inl thus ?thesis using a1 by (clarsimp simp: sum_set_defs(1))
64  next
65    case Inr thus ?thesis using a2 by (clarsimp simp: sum_set_defs(2))
66  qed
67next
68  fix f1 :: "'o \<Rightarrow> 'q" and f2 :: "'p \<Rightarrow> 'r"
69  show "setl \<circ> map_sum f1 f2 = image f1 \<circ> setl"
70    by (rule ext, unfold o_apply) (simp add: sum_set_defs(1) split: sum.split)
71next
72  fix f1 :: "'o \<Rightarrow> 'q" and f2 :: "'p \<Rightarrow> 'r"
73  show "setr \<circ> map_sum f1 f2 = image f2 \<circ> setr"
74    by (rule ext, unfold o_apply) (simp add: sum_set_defs(2) split: sum.split)
75next
76  show "card_order natLeq" by (rule natLeq_card_order)
77next
78  show "cinfinite natLeq" by (rule natLeq_cinfinite)
79next
80  fix x :: "'o + 'p"
81  show "|setl x| \<le>o natLeq"
82    apply (rule ordLess_imp_ordLeq)
83    apply (rule finite_iff_ordLess_natLeq[THEN iffD1])
84    by (simp add: sum_set_defs(1) split: sum.split)
85next
86  fix x :: "'o + 'p"
87  show "|setr x| \<le>o natLeq"
88    apply (rule ordLess_imp_ordLeq)
89    apply (rule finite_iff_ordLess_natLeq[THEN iffD1])
90    by (simp add: sum_set_defs(2) split: sum.split)
91next
92  fix R1 R2 S1 S2
93  show "rel_sum R1 R2 OO rel_sum S1 S2 \<le> rel_sum (R1 OO S1) (R2 OO S2)"
94    by (force elim: rel_sum.cases)
95next
96  fix R S
97  show "rel_sum R S = (\<lambda>x y.
98    \<exists>z. (setl z \<subseteq> {(x, y). R x y} \<and> setr z \<subseteq> {(x, y). S x y}) \<and>
99    map_sum fst fst z = x \<and> map_sum snd snd z = y)"
100  unfolding sum_set_defs relcompp.simps conversep.simps fun_eq_iff
101  by (fastforce elim: rel_sum.cases split: sum.splits)
102qed (auto simp: sum_set_defs fun_eq_iff pred_sum.simps split: sum.splits)
103
104inductive_set fsts :: "'a \<times> 'b \<Rightarrow> 'a set" for p :: "'a \<times> 'b" where
105  "fst p \<in> fsts p"
106inductive_set snds :: "'a \<times> 'b \<Rightarrow> 'b set" for p :: "'a \<times> 'b" where
107  "snd p \<in> snds p"
108
109lemma prod_set_defs[code]: "fsts = (\<lambda>p. {fst p})" "snds = (\<lambda>p. {snd p})"
110  by (auto intro: fsts.intros snds.intros elim: fsts.cases snds.cases)
111
112inductive
113  rel_prod :: "('a \<Rightarrow> 'b \<Rightarrow> bool) \<Rightarrow> ('c \<Rightarrow> 'd \<Rightarrow> bool) \<Rightarrow> 'a \<times> 'c \<Rightarrow> 'b \<times> 'd \<Rightarrow> bool" for R1 R2
114where
115  "\<lbrakk>R1 a b; R2 c d\<rbrakk> \<Longrightarrow> rel_prod R1 R2 (a, c) (b, d)"
116
117inductive
118  pred_prod :: "('a \<Rightarrow> bool) \<Rightarrow> ('b \<Rightarrow> bool) \<Rightarrow> 'a \<times> 'b \<Rightarrow> bool" for P1 P2
119where
120  "\<lbrakk>P1 a; P2 b\<rbrakk> \<Longrightarrow> pred_prod P1 P2 (a, b)"
121
122lemma rel_prod_inject [code, simp]:
123  "rel_prod R1 R2 (a, b) (c, d) \<longleftrightarrow> R1 a c \<and> R2 b d"
124  by (auto intro: rel_prod.intros elim: rel_prod.cases)
125
126lemma pred_prod_inject [code, simp]:
127  "pred_prod P1 P2 (a, b) \<longleftrightarrow> P1 a \<and> P2 b"
128  by (auto intro: pred_prod.intros elim: pred_prod.cases)
129
130lemma rel_prod_conv:
131  "rel_prod R1 R2 = (\<lambda>(a, b) (c, d). R1 a c \<and> R2 b d)"
132  by (rule ext, rule ext) auto
133
134definition
135  pred_fun :: "('a \<Rightarrow> bool) \<Rightarrow> ('b \<Rightarrow> bool) \<Rightarrow> ('a \<Rightarrow> 'b) \<Rightarrow> bool"
136where
137  "pred_fun A B = (\<lambda>f. \<forall>x. A x \<longrightarrow> B (f x))"
138
139lemma pred_funI: "(\<And>x. A x \<Longrightarrow> B (f x)) \<Longrightarrow> pred_fun A B f"
140  unfolding pred_fun_def by simp
141
142bnf "'a \<times> 'b"
143  map: map_prod
144  sets: fsts snds
145  bd: natLeq
146  rel: rel_prod
147  pred: pred_prod
148proof (unfold prod_set_defs)
149  show "map_prod id id = id" by (rule map_prod.id)
150next
151  fix f1 f2 g1 g2
152  show "map_prod (g1 \<circ> f1) (g2 \<circ> f2) = map_prod g1 g2 \<circ> map_prod f1 f2"
153    by (rule map_prod.comp[symmetric])
154next
155  fix x f1 f2 g1 g2
156  assume "\<And>z. z \<in> {fst x} \<Longrightarrow> f1 z = g1 z" "\<And>z. z \<in> {snd x} \<Longrightarrow> f2 z = g2 z"
157  thus "map_prod f1 f2 x = map_prod g1 g2 x" by (cases x) simp
158next
159  fix f1 f2
160  show "(\<lambda>x. {fst x}) \<circ> map_prod f1 f2 = image f1 \<circ> (\<lambda>x. {fst x})"
161    by (rule ext, unfold o_apply) simp
162next
163  fix f1 f2
164  show "(\<lambda>x. {snd x}) \<circ> map_prod f1 f2 = image f2 \<circ> (\<lambda>x. {snd x})"
165    by (rule ext, unfold o_apply) simp
166next
167  show "card_order natLeq" by (rule natLeq_card_order)
168next
169  show "cinfinite natLeq" by (rule natLeq_cinfinite)
170next
171  fix x
172  show "|{fst x}| \<le>o natLeq"
173    by (rule ordLess_imp_ordLeq) (simp add: finite_iff_ordLess_natLeq[symmetric])
174next
175  fix x
176  show "|{snd x}| \<le>o natLeq"
177    by (rule ordLess_imp_ordLeq) (simp add: finite_iff_ordLess_natLeq[symmetric])
178next
179  fix R1 R2 S1 S2
180  show "rel_prod R1 R2 OO rel_prod S1 S2 \<le> rel_prod (R1 OO S1) (R2 OO S2)" by auto
181next
182  fix R S
183  show "rel_prod R S = (\<lambda>x y.
184    \<exists>z. ({fst z} \<subseteq> {(x, y). R x y} \<and> {snd z} \<subseteq> {(x, y). S x y}) \<and>
185      map_prod fst fst z = x \<and> map_prod snd snd z = y)"
186  unfolding prod_set_defs rel_prod_inject relcompp.simps conversep.simps fun_eq_iff
187  by auto
188qed auto
189
190bnf "'a \<Rightarrow> 'b"
191  map: "(\<circ>)"
192  sets: range
193  bd: "natLeq +c |UNIV :: 'a set|"
194  rel: "rel_fun (=)"
195  pred: "pred_fun (\<lambda>_. True)"
196proof
197  fix f show "id \<circ> f = id f" by simp
198next
199  fix f g show "(\<circ>) (g \<circ> f) = (\<circ>) g \<circ> (\<circ>) f"
200  unfolding comp_def[abs_def] ..
201next
202  fix x f g
203  assume "\<And>z. z \<in> range x \<Longrightarrow> f z = g z"
204  thus "f \<circ> x = g \<circ> x" by auto
205next
206  fix f show "range \<circ> (\<circ>) f = (`) f \<circ> range"
207    by (auto simp add: fun_eq_iff)
208next
209  show "card_order (natLeq +c |UNIV| )" (is "_ (_ +c ?U)")
210  apply (rule card_order_csum)
211  apply (rule natLeq_card_order)
212  by (rule card_of_card_order_on)
213(*  *)
214  show "cinfinite (natLeq +c ?U)"
215    apply (rule cinfinite_csum)
216    apply (rule disjI1)
217    by (rule natLeq_cinfinite)
218next
219  fix f :: "'d => 'a"
220  have "|range f| \<le>o | (UNIV::'d set) |" (is "_ \<le>o ?U") by (rule card_of_image)
221  also have "?U \<le>o natLeq +c ?U" by (rule ordLeq_csum2) (rule card_of_Card_order)
222  finally show "|range f| \<le>o natLeq +c ?U" .
223next
224  fix R S
225  show "rel_fun (=) R OO rel_fun (=) S \<le> rel_fun (=) (R OO S)" by (auto simp: rel_fun_def)
226next
227  fix R
228  show "rel_fun (=) R = (\<lambda>x y.
229    \<exists>z. range z \<subseteq> {(x, y). R x y} \<and> fst \<circ> z = x \<and> snd \<circ> z = y)"
230  unfolding rel_fun_def subset_iff by (force simp: fun_eq_iff[symmetric])
231qed (auto simp: pred_fun_def)
232
233end
234