theory LFex

imports Nominal QuotMain

begin

atom_decl name id

nominal_datatype kind = 

    Type

  | KPi "ty" "name" "kind"

and ty =  

    TConst "id"

  | TApp "ty" "trm"

  | TPi "ty" "name" "ty"

and trm = 

    Const "id"

  | Var "name"

  | App "trm" "trm"

  | Lam "ty" "name" "trm" 

function

    fv_kind :: "kind \<Rightarrow> name set"

and fv_ty   :: "ty \<Rightarrow> name set"

and fv_trm  :: "trm \<Rightarrow> name set"

where

  "fv_kind (Type) = {}"

| "fv_kind (KPi A x K) = (fv_ty A) \<union> ((fv_kind K) - {x})"

| "fv_ty (TConst i) = {}"

| "fv_ty (TApp A M) = (fv_ty A) \<union> (fv_trm M)"

| "fv_ty (TPi A x B) = (fv_ty A) \<union> ((fv_ty B) - {x})"

| "fv_trm (Const i) = {}"

| "fv_trm (Var x) = {x}"

| "fv_trm (App M N) = (fv_trm M) \<union> (fv_trm N)"

| "fv_trm (Lam A x M) = (fv_ty A) \<union> ((fv_trm M) - {x})"

sorry

termination fv_kind sorry

inductive

    akind :: "kind \<Rightarrow> kind \<Rightarrow> bool" ("_ \<approx>ki _" [100, 100] 100)

and aty   :: "ty \<Rightarrow> ty \<Rightarrow> bool"     ("_ \<approx>ty _" [100, 100] 100)

and atrm  :: "trm \<Rightarrow> trm \<Rightarrow> bool"   ("_ \<approx>tr _" [100, 100] 100)

where

  a1:  "(Type) \<approx>ki (Type)"

| a21: "\<lbrakk>A \<approx>ty A'; K \<approx>ki K'\<rbrakk> \<Longrightarrow> (KPi A x K) \<approx>ki (KPi A' x K')"

| a22: "\<lbrakk>A \<approx>ty A'; K \<approx>ki ([(x,x')]\<bullet>K'); x \<notin> (fv_ty A'); x \<notin> ((fv_kind K') - {x'})\<rbrakk> 

        \<Longrightarrow> (KPi A x K) \<approx>ki (KPi A' x' K')"

| a3:  "i = j \<Longrightarrow> (TConst i) \<approx>ty (TConst j)"

| a4:  "\<lbrakk>A \<approx>ty A'; M \<approx>tr M'\<rbrakk> \<Longrightarrow> (TApp A M) \<approx>ty (TApp A' M')"

| a51: "\<lbrakk>A \<approx>ty A'; B \<approx>ty B'\<rbrakk> \<Longrightarrow> (TPi A x B) \<approx>ty (TPi A' x B')"

| a52: "\<lbrakk>A \<approx>ty A'; B \<approx>ty ([(x,x')]\<bullet>B'); x \<notin> (fv_ty B'); x \<notin> ((fv_ty B') - {x'})\<rbrakk> 

        \<Longrightarrow> (TPi A x B) \<approx>ty (TPi A' x' B')"

| a6:  "i = j \<Longrightarrow> (Const i) \<approx>trm (Const j)"

| a7:  "x = y \<Longrightarrow> (Var x) \<approx>trm (Var y)"

| a8:  "\<lbrakk>M \<approx>trm M'; N \<approx>tr N'\<rbrakk> \<Longrightarrow> (App M N) \<approx>tr (App M' N')"

| a91: "\<lbrakk>A \<approx>ty A'; M \<approx>tr M'\<rbrakk> \<Longrightarrow> (Lam A x M) \<approx>tr (Lam A' x M')"

| a92: "\<lbrakk>A \<approx>ty A'; M \<approx>tr ([(x,x')]\<bullet>M'); x \<notin> (fv_ty B'); x \<notin> ((fv_trm M') - {x'})\<rbrakk> 

        \<Longrightarrow> (Lam A x M) \<approx>tr (Lam A' x' M')"

lemma al_refl:

  fixes K::"kind" 

  and   A::"ty"

  and   M::"trm"

  shows "K \<approx>ki K"

  and   "A \<approx>ty A"

  and   "M \<approx>tr M"

  apply(induct K and A and M rule: kind_ty_trm.inducts)

  apply(auto intro: akind_aty_atrm.intros)

  done

lemma alpha_EQUIVs:

  shows "EQUIV akind"

  and   "EQUIV aty"

  and   "EQUIV atrm"

sorry

quotient KIND = kind / akind

  by (rule alpha_EQUIVs)

quotient TY = ty / aty

   and   TRM = trm / atrm

  by (auto intro: alpha_EQUIVs)

print_quotients

quotient_def 

  TYP :: "KIND"

where

  "TYP \<equiv> Type"

quotient_def 

  KPI :: "TY \<Rightarrow> name \<Rightarrow> KIND \<Rightarrow> KIND"

where

  "KPI \<equiv> KPi"

quotient_def 

  TCONST :: "id \<Rightarrow> TY"

where

  "TCONST \<equiv> TConst"

quotient_def 

  TAPP :: "TY \<Rightarrow> TRM \<Rightarrow> TY"

where

  "TAPP \<equiv> TApp"

quotient_def 

  TPI :: "TY \<Rightarrow> name \<Rightarrow> TY \<Rightarrow> TY"

where

  "TPI \<equiv> TPi"

(* FIXME: does not work with CONST *)

quotient_def 

  CONS :: "id \<Rightarrow> TRM"

where

  "CONS \<equiv> Const"

quotient_def 

  VAR :: "name \<Rightarrow> TRM"

where

  "VAR \<equiv> Var"

quotient_def 

  APP :: "TRM \<Rightarrow> TRM \<Rightarrow> TRM"

where

  "APP \<equiv> App"

quotient_def 

  LAM :: "TY \<Rightarrow> name \<Rightarrow> TRM \<Rightarrow> TRM"

where

  "LAM \<equiv> Lam"

thm TYP_def

thm KPI_def

thm TCONST_def

thm TAPP_def

thm TPI_def

thm VAR_def

thm CONS_def

thm APP_def

thm LAM_def

(* FIXME: print out a warning if the type contains a liftet type, like kind \<Rightarrow> name set *)

quotient_def 

  FV_kind :: "KIND \<Rightarrow> name set"

where

  "FV_kind \<equiv> fv_kind"

quotient_def 

  FV_ty :: "TY \<Rightarrow> name set"

where

  "FV_ty \<equiv> fv_ty"

quotient_def 

  FV_trm :: "TRM \<Rightarrow> name set"

where

  "FV_trm \<equiv> fv_trm"

thm FV_kind_def

thm FV_ty_def

thm FV_trm_def

(* FIXME: does not work yet *)

(*

overloading

    perm_kind \<equiv> "perm :: 'x prm \<Rightarrow> KIND \<Rightarrow> KIND"   (unchecked)

    perm_ty   \<equiv> "perm :: 'x prm \<Rightarrow> TY \<Rightarrow> TY"       (unchecked)

    perm_trm  \<equiv> "perm :: 'x prm \<Rightarrow> TRM \<Rightarrow> TRM"     (unchecked) 

begin

quotient_def 

  perm_kind :: "'x prm \<Rightarrow> KIND \<Rightarrow> KIND"

where

  "perm_kind \<equiv> (perm::'x prm \<Rightarrow> KIND \<Rightarrow> KIND)"

end

*)