Theory Static

theory Static
imports Values Types
(*  Title:      ZF/Coind/Static.thy
Author: Jacob Frost, Cambridge University Computer Laboratory
Copyright 1995 University of Cambridge
*)


theory Static imports Values Types begin

(*** Basic correspondence relation -- not completely specified, as it is a
parameter of the proof. A concrete version could be defined inductively.
***)


axiomatization isof :: "[i,i] => o"
where isof_app: "[|isof(c1,t_fun(t1,t2)); isof(c2,t1)|] ==> isof(c_app(c1,c2),t2)"

(*Its extension to environments*)

definition
isofenv :: "[i,i] => o" where
"isofenv(ve,te) ==
ve_dom(ve) = te_dom(te) &
(∀x ∈ ve_dom(ve).
∃c ∈ Const. ve_app(ve,x) = v_const(c) & isof(c,te_app(te,x)))"



(*** Elaboration ***)

consts ElabRel :: i

inductive
domains "ElabRel" "TyEnv * Exp * Ty"
intros
constI [intro!]:
"[| te ∈ TyEnv; c ∈ Const; t ∈ Ty; isof(c,t) |] ==>
<te,e_const(c),t> ∈ ElabRel"

varI [intro!]:
"[| te ∈ TyEnv; x ∈ ExVar; x ∈ te_dom(te) |] ==>
<te,e_var(x),te_app(te,x)> ∈ ElabRel"

fnI [intro!]:
"[| te ∈ TyEnv; x ∈ ExVar; e ∈ Exp; t1 ∈ Ty; t2 ∈ Ty;
<te_owr(te,x,t1),e,t2> ∈ ElabRel |] ==>
<te,e_fn(x,e),t_fun(t1,t2)> ∈ ElabRel"

fixI [intro!]:
"[| te ∈ TyEnv; f ∈ ExVar; x ∈ ExVar; t1 ∈ Ty; t2 ∈ Ty;
<te_owr(te_owr(te,f,t_fun(t1,t2)),x,t1),e,t2> ∈ ElabRel |] ==>
<te,e_fix(f,x,e),t_fun(t1,t2)> ∈ ElabRel"

appI [intro]:
"[| te ∈ TyEnv; e1 ∈ Exp; e2 ∈ Exp; t1 ∈ Ty; t2 ∈ Ty;
<te,e1,t_fun(t1,t2)> ∈ ElabRel;
<te,e2,t1> ∈ ElabRel |] ==> <te,e_app(e1,e2),t2> ∈ ElabRel"

type_intros te_appI Exp.intros Ty.intros


inductive_cases
elab_constE [elim!]: "<te,e_const(c),t> ∈ ElabRel"
and elab_varE [elim!]: "<te,e_var(x),t> ∈ ElabRel"
and elab_fnE [elim]: "<te,e_fn(x,e),t> ∈ ElabRel"
and elab_fixE [elim!]: "<te,e_fix(f,x,e),t> ∈ ElabRel"
and elab_appE [elim]: "<te,e_app(e1,e2),t> ∈ ElabRel"

declare ElabRel.dom_subset [THEN subsetD, dest]

end