--- a/Nominal/Ex/SFT/LambdaTerms.thy Tue Feb 19 05:38:46 2013 +0000
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,83 +0,0 @@
-header {* Definition of Lambda terms and convertibility *}
-
-theory LambdaTerms imports "../../Nominal2" begin
-
-lemma [simp]: "supp x = {} \<Longrightarrow> y \<sharp> x"
- unfolding fresh_def by blast
-
-atom_decl name
-
-nominal_datatype lam =
- Var "name"
-| App "lam" "lam"
-| Lam x::"name" l::"lam" binds x in l ("Lam [_]. _" [100, 100] 100)
-
-notation
- App (infixl "\<cdot>" 98) and
- Lam ("\<integral> _. _" [97, 97] 99)
-
-nominal_primrec
- subst :: "lam \<Rightarrow> name \<Rightarrow> lam \<Rightarrow> lam" ("_ [_ ::= _]" [90, 90, 90] 90)
-where
- "(Var x)[y ::= s] = (if x = y then s else (Var x))"
-| "(t1 \<cdot> t2)[y ::= s] = (t1[y ::= s]) \<cdot> (t2[y ::= s])"
-| "atom x \<sharp> (y, s) \<Longrightarrow> (\<integral>x. t)[y ::= s] = \<integral>x.(t[y ::= s])"
-proof auto
- fix a b :: lam and aa :: name and P
- assume "\<And>x y s. a = Var x \<and> aa = y \<and> b = s \<Longrightarrow> P"
- "\<And>t1 t2 y s. a = t1 \<cdot> t2 \<and> aa = y \<and> b = s \<Longrightarrow> P"
- "\<And>x y s t. \<lbrakk>atom x \<sharp> (y, s); a = \<integral> x. t \<and> aa = y \<and> b = s\<rbrakk> \<Longrightarrow> P"
- then show "P"
- by (rule_tac y="a" and c="(aa, b)" in lam.strong_exhaust)
- (blast, blast, simp add: fresh_star_def)
-next
- fix x :: name and t and xa :: name and ya sa ta
- assume *: "eqvt_at subst_sumC (t, ya, sa)"
- "atom x \<sharp> (ya, sa)" "atom xa \<sharp> (ya, sa)"
- "[[atom x]]lst. t = [[atom xa]]lst. ta"
- then show "[[atom x]]lst. subst_sumC (t, ya, sa) = [[atom xa]]lst. subst_sumC (ta, ya, sa)"
- apply -
- apply (erule Abs_lst1_fcb)
- apply(simp (no_asm) add: Abs_fresh_iff)
- apply(drule_tac a="atom xa" in fresh_eqvt_at)
- apply(simp add: finite_supp)
- apply(simp_all add: fresh_Pair_elim Abs_fresh_iff Abs1_eq_iff)
- apply(subgoal_tac "(atom x \<rightleftharpoons> atom xa) \<bullet> ya = ya")
- apply(subgoal_tac "(atom x \<rightleftharpoons> atom xa) \<bullet> sa = sa")
- apply(simp add: atom_eqvt eqvt_at_def)
- apply(rule perm_supp_eq, simp add: supp_swap fresh_star_def fresh_Pair)+
- done
-next
- show "eqvt subst_graph" unfolding eqvt_def subst_graph_def
- by (rule, perm_simp, rule)
-qed
-
-termination (eqvt) by lexicographic_order
-
-lemma forget[simp]:
- shows "atom x \<sharp> t \<Longrightarrow> t[x ::= s] = t"
- by (nominal_induct t avoiding: x s rule: lam.strong_induct)
- (auto simp add: lam.fresh fresh_at_base)
-
-lemma forget_closed[simp]: "supp t = {} \<Longrightarrow> t[x ::= s] = t"
- by (simp add: fresh_def)
-
-lemma subst_id[simp]: "M [x ::= Var x] = M"
- by (rule_tac lam="M" and c="x" in lam.strong_induct)
- (simp_all add: fresh_star_def lam.fresh fresh_Pair)
-
-inductive
- beta :: "lam \<Rightarrow> lam \<Rightarrow> bool" (infix "\<approx>" 80)
-where
- bI: "(\<integral>x. M) \<cdot> N \<approx> M[x ::= N]"
-| b1: "M \<approx> M"
-| b2: "M \<approx> N \<Longrightarrow> N \<approx> M"
-| b3: "M \<approx> N \<Longrightarrow> N \<approx> L \<Longrightarrow> M \<approx> L"
-| b4: "M \<approx> N \<Longrightarrow> Z \<cdot> M \<approx> Z \<cdot> N"
-| b5: "M \<approx> N \<Longrightarrow> M \<cdot> Z \<approx> N \<cdot> Z"
-| b6: "M \<approx> N \<Longrightarrow> \<integral>x. M \<approx> \<integral>x. N"
-
-lemmas [trans] = b3
-equivariance beta
-
-end