:: A Tree of Execution of a Macroinstruction
::  by Artur Korni{\l}owicz

environ

 vocabularies NUMBERS, ORDINAL1, RELAT_1, FUNCOP_1, FUNCT_1, CARD_1, WELLORD2,
      XBOOLE_0, TARSKI, SUBSET_1, ZFMISC_1, WELLORD1, ORDINAL2, FINSEQ_2,
      FINSEQ_1, TREES_1, TREES_2, NAT_1, XXREAL_0, ARYTM_3, ORDINAL4, GOBOARD5,
      AMI_1, AMISTD_1, GLIB_000, AMISTD_2, AMISTD_3, PARTFUN1, EXTPRO_1,
      QUANTAL1, MEMSTR_0;
 notations TARSKI, XBOOLE_0, ZFMISC_1, SUBSET_1, CARD_1, ORDINAL1, ORDINAL2,
      NUMBERS, XXREAL_0, XCMPLX_0, NAT_1, RELAT_1, FUNCT_1, PARTFUN1, FUNCT_2,
      BINOP_1, WELLORD1, WELLORD2, FUNCOP_1, FINSEQ_1, FINSEQ_2, TREES_1,
      TREES_2, VALUED_1, MEASURE6, STRUCT_0, MEMSTR_0, COMPOS_1, EXTPRO_1,
      AMISTD_1;
 constructors WELLORD2, BINOP_1, AMISTD_2, RELSET_1, TREES_2, PRE_POLY,
      AMISTD_1, FUNCOP_1, DOMAIN_1, NUMBERS, TREES_3;
 registrations RELAT_1, ORDINAL1, FUNCOP_1, XXREAL_0, CARD_1, MEMBERED,
      FINSEQ_1, TREES_2, FINSEQ_6, VALUED_0, FINSEQ_2, CARD_5, TREES_1,
      AMISTD_2, COMPOS_1, EXTPRO_1, MEASURE6;
 requirements BOOLE, SUBSET, NUMERALS;
 definitions RELAT_1, TARSKI, XBOOLE_0, FUNCT_1;
 equalities FINSEQ_2, FUNCOP_1, AFINSQ_1, COMPOS_1, ORDINAL1;
 expansions TARSKI, FUNCT_1;
 theorems AMISTD_1, NAT_1, ORDINAL1, CARD_1, TREES_2, TREES_1, FINSEQ_1,
      FUNCT_1, RELAT_1, FINSEQ_3, FINSEQ_5, TARSKI, CARD_5, FINSEQ_2, FUNCOP_1,
      XXREAL_0, PARTFUN1, TREES_9, VALUED_1;
 schemes TREES_2, NAT_1, HILBERT2, ORDINAL2, BINOP_1;

begin

reserve x, y, z, X for set,
  m, n for Nat,
  O for Ordinal,
  R, S for Relation;

reserve
  N for with_zero set,
  S for
  standard IC-Ins-separated non empty with_non-empty_values AMI-Struct over N,
  L, l1 for Nat,
  J for Instruction of S,
  F for Subset of NAT;

:: LocSeq

definition
  let N be with_zero set,
  S be standard IC-Ins-separated
   non empty with_non-empty_values AMI-Struct over N, M be Subset of NAT;
  deffunc F(object) = canonical_isomorphism_of (RelIncl order_type_of
  RelIncl M,RelIncl M).$1;
  func LocSeq(M,S) -> Sequence of NAT means
  :Def1:
  dom it = card M & for m
being set st m in card M holds it.m = (canonical_isomorphism_of (RelIncl
  order_type_of RelIncl M, RelIncl M).m);
  existence
  proof
    consider f being Sequence such that
A1: dom f = card M and
A2: for A being Ordinal st A in card M holds f.A = F(A) from ORDINAL2:
    sch 2;
    f is NAT-valued
    proof
      let y be object;
      assume y in rng f;
      then consider x being object such that
A3:   x in dom f & y = f.x by FUNCT_1:def 3;
      reconsider x as set by TARSKI:1;
      F(x) in NAT by ORDINAL1:def 12;
      hence thesis by A1,A2,A3;
    end;
    then reconsider f as Sequence of NAT;
    take f;
    thus dom f = card M by A1;
    let m be set;
    assume m in card M;
    hence thesis by A2;
  end;
  uniqueness
  proof
    let f, g be Sequence of NAT such that
A4: dom f = card M and
A5: for m being set st m in card M holds f.m = F(m) and
A6: dom g = card M and
A7: for m being set st m in card M holds g.m = F(m);
    for x being object st x in dom f holds f.x = g.x
    proof
      let x be object such that
A8:   x in dom f;
      thus f.x = F(x) by A4,A5,A8
        .= g.x by A4,A7,A8;
    end;
    hence thesis by A4,A6;
  end;
end;

theorem
  F = {n} implies LocSeq(F,S) = 0 .--> n
proof
  assume
A1: F = {n};
  then
A2: card F = {0} by CARD_1:30,49;
  {n} c= omega
  by ORDINAL1:def 12;
  then
A3: canonical_isomorphism_of(RelIncl order_type_of RelIncl {n}, RelIncl { n}
  ).0 = (0 .--> n).0 by CARD_5:38
    .= n by FUNCOP_1:72;
A4: dom LocSeq(F,S) = card F by Def1;
A5: for a being object st a in dom LocSeq(F,S) holds (LocSeq(F,S)).a
 = (0 .--> n ) . a
  proof
    let a be object;
    assume
A6: a in dom LocSeq(F,S);
    then
A7: a = 0 by A4,A2,TARSKI:def 1;
    thus (LocSeq(F,S)).a = (canonical_isomorphism_of
     (RelIncl order_type_of
    RelIncl F, RelIncl F).a) by A4,A6,Def1
      .= (0 .--> n).a by A1,A3,A7,FUNCOP_1:72;
  end;
  thus thesis by A1,A4,A5,CARD_1:30,49;
end;

registration
  let N be with_zero set,
  S be standard IC-Ins-separated
 non empty with_non-empty_values AMI-Struct over N, M be Subset of NAT;
  cluster LocSeq(M,S) -> one-to-one;
  coherence
  proof
    set f = LocSeq(M,S);
    set C = canonical_isomorphism_of (RelIncl order_type_of RelIncl M,RelIncl
    M);
    let x1,x2 be object such that
A1: x1 in dom f & x2 in dom f and
A2: f.x1 = f.x2;
A3: dom f = card M by Def1;
    then
A4:  f.x1 = C.x1 & f.x2 = C.x2 by A1,Def1;
A5: card M c= order_type_of RelIncl M by CARD_5:39;
    consider phi being Ordinal-Sequence such that
A6: phi = C and
A7: phi is increasing and
A8: dom phi = order_type_of RelIncl M and
    rng phi = M by CARD_5:5;
    phi is one-to-one by A7,CARD_5:11;
    hence thesis by A1,A2,A3,A4,A6,A8,A5;
  end;
end;

:: Tree of Execution

definition  let N be with_zero set,
  S be standard IC-Ins-separated
  non empty with_non-empty_values AMI-Struct over N,
  M be non empty preProgram of S;
  func ExecTree(M) -> DecoratedTree of NAT means
  :Def2:
  it.{} = FirstLoc(M) &
  for t being Element of dom it holds
  succ t = { t^<*k*> where k is Nat: k in card NIC(M/.(it.t),it.t) }
   & for m being Nat st m in card
  NIC(M/.(it.t),it.t) holds it.(t^<*m*>) = (LocSeq(NIC(M/.(it.t),it.t),S)).m;
  existence
  proof
    defpred S[Nat,Nat] means $1 in card NIC(M/.$2,$2);
    reconsider n = FirstLoc(M) as Nat;
    defpred P[set,Nat,set] means ex l being Nat
 st l = $1 & ($2 in dom LocSeq(NIC(M/.l,l),S) implies
 $3 = (LocSeq(NIC(M/.l,l),S)).$2) &
  (not $2 in dom LocSeq(NIC(M/.l,l),S) implies $3 = 0);
    set D = NAT;
A1: for x, y being Element of NAT ex z being Element of NAT st P[x,y,z]
    proof
      let x, y be Element of NAT;
      reconsider z = (LocSeq(NIC(M/.x,x),S)).y as Element of NAT
          by ORDINAL1:def 12;
      per cases;
      suppose
A2:     y in dom LocSeq(NIC(M/.x,x),S);
        take z;
        thus thesis by A2;
      end;
      suppose
A3:     not y in dom LocSeq(NIC(M/.x,x),S);
        reconsider il = 0 as Element of NAT;
        take il;
        thus thesis by A3;
      end;
    end;
    consider f be Function of [:D,NAT:],D such that
A4: for l,n being Element of NAT holds P[l,n,f.(l,n)] from BINOP_1:sch 3(A1);
A5: for d being Element of NAT, k1, k2 being Nat st k1 <= k2 &
    S[k2,d] holds S[k1,d]
    proof let d be Element of NAT, k1, k2 be Nat such that
A6:   k1 <= k2 and
A7:   S[k2,d];
      Segm k2 in card NIC(M/.d,d) by A7;
      then Segm k1 in card NIC(M/.d,d) by A6,NAT_1:39,ORDINAL1:12;
     hence thesis;
    end;
    reconsider n as Element of NAT;
    consider T being DecoratedTree of NAT such that
A8: T.{} = n and
A9: for t being Element of dom T
      holds succ t = { t^<*k*> where k is Nat: S[k,T.t]} &
     for n being Nat st S[n,T.t] holds T.(t^
    <*n*>) = f.(T.t,n) from TREES_2:sch 10(A5);
    take T;
    thus T.{} = FirstLoc(M) by A8;
    let t be Element of dom T;
    thus
     succ t ={ t^<*k*> where k is Nat: S[k,T.t]} by A9;
    reconsider n = T.t as Element of NAT;
    let m be Nat;
A10:  m in NAT by ORDINAL1:def 12;
    consider l being Nat such that
A11: l = n and
A12: m in dom LocSeq(NIC(M/.l,l),S) implies
 f.(n,m)= (LocSeq(NIC(M/.l,l),S)).m and
    not m in dom LocSeq(NIC(M/.l,l),S) implies f.(n,m) = 0 by A4,A10;
   assume m in card NIC(M/.(T.t),T.t);
    hence thesis by A9,A11,A12,Def1;
  end;
  uniqueness
  proof
    let T1,T2 be DecoratedTree of NAT such that
A13: T1.{} = FirstLoc(M) and
A14: for t being Element of dom T1 holds succ t = { t^<*k*> where k is
Nat: k in card NIC(M/.(T1.t),T1.t)} & for m being Nat st
m in card NIC(M/.(T1.t),T1.t) holds T1.(t^<*m*>) =
     (LocSeq(NIC(M/.(T1.t),T1.t),S)).m and
A15: T2.{} = FirstLoc(M) and
A16: for t being Element of dom T2 holds succ t = { t^<*k*> where k is
Nat: k in card NIC(M/.(T2.t),T2.t)} & for m being Nat st
m in card NIC(M/.(T2.t),T2.t) holds T2.(t^<*m*>) =
 (LocSeq(NIC(M/.(T2.t),T2.t),S)).m;
    defpred P[Nat] means dom T1-level $1 = dom T2-level $1;
A17: for n being Nat st P[n] holds P[n+1]
    proof
      let n be Nat such that
A18:  P[n];
      set U2 = { succ w where w is Element of dom T2 : len w = n };
      set U1 = { succ w where w is Element of dom T1 : len w = n };
A19:  dom T2-level n = {v where v is Element of dom T2: len v = n} by
TREES_2:def 6;
A20:  dom T1-level n = {v where v is Element of dom T1: len v = n} by
TREES_2:def 6;
A21:  union U1 = union U2
      proof
        hereby
          let a be object;
          assume a in union U1;
          then consider A being set such that
A22:      a in A and
A23:      A in U1 by TARSKI:def 4;
          consider w being Element of dom T1 such that
A24:      A = succ w and
A25:      len w = n by A23;
          w in dom T1-level n by A20,A25;
          then consider v being Element of dom T2 such that
A26:      w = v and
A27:      len v = n by A18,A19;
A28:      w = w|Seg len w by FINSEQ_3:49;
          defpred R[Nat] means $1 <= len w & w|Seg $1 in dom T1 & v
          |Seg $1 in dom T2 implies T1.(w|Seg $1) = T2.(w|Seg $1);
A29:      for n being Nat st R[n] holds R[n+1]
          proof
            let n be Nat;
            assume that
A30:        R[n] and
A31:        n+1 <= len w and
A32:        w|Seg (n+1) in dom T1 and
A33:        v|Seg (n+1) in dom T2;
            set t1 = w|Seg n;
A34:        1 <= n+1 by NAT_1:11;
A35:        len(w|Seg(n+1)) = n+1 by A31,FINSEQ_1:17;
            then len(w|Seg(n+1)) in Seg(n+1) by A34,FINSEQ_1:1;
            then
A36:        w.(n+1) = (w|Seg(n+1)).len(w|Seg(n+1)) by A35,FUNCT_1:49;
            n+1 in dom w by A31,A34,FINSEQ_3:25;
            then
A37:        w|Seg(n+1) = t1^<*(w|Seg(n+1)).len (w|Seg(n+1))*> by A36,
FINSEQ_5:10;
A38:        n <= n+1 by NAT_1:11;
            then
A39:        Seg n c= Seg(n+1) by FINSEQ_1:5;
            then v|Seg n = v|Seg(n+1)|Seg n by RELAT_1:74;
            then
A40:        v|Seg n is_a_prefix_of v|Seg(n+1) by TREES_1:def 1;
            w|Seg n = w|Seg(n+1)|Seg n by A39,RELAT_1:74;
            then w|Seg n is_a_prefix_of w|Seg(n+1) by TREES_1:def 1;
            then reconsider t1 as Element of dom T1 by A32,TREES_1:20;
            reconsider t2 = t1 as Element of dom T2 by A26,A33,A40,TREES_1:20;
A41:        succ t1 = { t1^<*k*> where k is Nat: k in card NIC
            (M/.(T1.t1),T1.t1)} by A14;
            t1^<*(w|Seg(n+1)).len(w|Seg(n+1))*> in succ t1 by A32,A37,
TREES_2:12;
            then consider k being Nat such that
A42:        t1^<*(w|Seg(n+1)).len(w|Seg(n+1))*> = t1^<*k*> and
A43:        k in card NIC(M/.(T1.t1),T1.t1) by A41;
A44:        (w|Seg(n+1)).len(w|Seg(n+1)) in card NIC(M/.(T2.t2),T2.t2)
            by A30,A31,A33,A38,A40,A42,A43,FINSEQ_2:17,TREES_1:20,XXREAL_0:2;
            k = (w|Seg(n+1)).len(w|Seg(n+1)) by A42,FINSEQ_2:17;
            hence
            T1.(w|Seg(n+1)) = (LocSeq(NIC(M/.(T1.t1),T1.t1),S)).((w|Seg(n+1
            )).len (w|Seg(n+1))) by A14,A37,A43
              .= T2.(w|Seg(n+1)) by A16,A30,A31,A33,A38,A40,A37,A44,
TREES_1:20,XXREAL_0:2;
          end;
A45:      R[0] by A13,A15;
          for n being Nat holds R[n] from NAT_1:sch 2(A45,A29);
          then
A46:      T1.w = T2.w by A26,A28;
A47:      succ v in U2 by A27;
          succ v = {v^<*k*> where k is Nat:
           k in card NIC(M/.(T2.v),T2.v)} &
           succ w = {w^<*k*> where k is Nat:
            k in card NIC(M/.(T1.w),T1.w)} by A14,A16;
          hence a in union U2 by A22,A24,A26,A46,A47,TARSKI:def 4;
        end;
        let a be object;
        assume a in union U2;
        then consider A being set such that
A48:    a in A and
A49:    A in U2 by TARSKI:def 4;
        consider w being Element of dom T2 such that
A50:    A = succ w and
A51:    len w = n by A49;
        w in dom T2-level n by A19,A51;
        then consider v being Element of dom T1 such that
A52:    w = v and
A53:    len v = n by A18,A20;
A54:    w = w|Seg len w by FINSEQ_3:49;
        defpred R[Nat] means $1 <= len w & w|Seg $1 in dom T1 & v|
        Seg $1 in dom T2 implies T1.(w|Seg $1) = T2.(w|Seg $1);
A55:    for n being Nat st R[n] holds R[n+1]
        proof
          let n be Nat;
          assume that
A56:      R[n] and
A57:      n+1 <= len w and
A58:      w|Seg (n+1) in dom T1 and
A59:      v|Seg (n+1) in dom T2;
          set t1 = w|Seg n;
A60:      1 <= n+1 by NAT_1:11;
A61:      len(w|Seg(n+1)) = n+1 by A57,FINSEQ_1:17;
          then len(w|Seg(n+1)) in Seg(n+1) by A60,FINSEQ_1:1;
          then
A62:      w.(n+1) = (w|Seg(n+1)).len(w|Seg(n+1)) by A61,FUNCT_1:49;
          n+1 in dom w by A57,A60,FINSEQ_3:25;
          then
A63:      w|Seg(n+1) = t1^<*(w|Seg(n+1)).len (w|Seg(n+1))*> by A62,FINSEQ_5:10;
A64:      n <= n+1 by NAT_1:11;
          then
A65:      Seg n c= Seg(n+1) by FINSEQ_1:5;
          then v|Seg n = v|Seg(n+1)|Seg n by RELAT_1:74;
          then
A66:      v|Seg n is_a_prefix_of v|Seg(n+1) by TREES_1:def 1;
          w|Seg n = w|Seg(n+1)|Seg n by A65,RELAT_1:74;
          then w|Seg n is_a_prefix_of w|Seg(n+1) by TREES_1:def 1;
          then reconsider t1 as Element of dom T1 by A58,TREES_1:20;
          reconsider t2 = t1 as Element of dom T2 by A52,A59,A66,TREES_1:20;
A67:      succ t1 = { t1^<*k*> where k is Nat: k in card NIC(
          M/.(T1.t1),T1.t1)} by A14;
          t1^<*(w|Seg(n+1)).len(w|Seg(n+1))*> in succ t1 by A58,A63,
TREES_2:12;
          then consider k being Nat such that
A68:      t1^<*(w|Seg(n+1)).len(w|Seg(n+1))*> = t1^<*k*> and
A69:      k in card NIC(M/.(T1.t1),T1.t1) by A67;
A70:      (w|Seg(n+1)).len(w|Seg(n+1)) in card NIC(M/.(T2.t2),T2.t2) by A56,A57
,A59,A64,A66,A68,A69,FINSEQ_2:17,TREES_1:20,XXREAL_0:2;
          k = (w|Seg(n+1)).len(w|Seg(n+1)) by A68,FINSEQ_2:17;
          hence
          T1.(w|Seg(n+1)) = (LocSeq(NIC(M/.(T1.t1),T1.t1),S)).((w|Seg(n+1))
          .len(w|Seg(n+1))) by A14,A63,A69
            .= T2.(w|Seg(n+1)) by A16,A56,A57,A59,A64,A66,A63,A70,
TREES_1:20,XXREAL_0:2;
        end;
A71:    R[0] by A13,A15;
        for n being Nat holds R[n] from NAT_1:sch 2(A71,A55);
        then
A72:    T1.w = T2.w by A52,A54;
A73:    succ v in U1 by A53;
        succ v = {v^<*k*> where k is Nat:
         k in card NIC(M/.(T1.v),T1.v)} &
         succ w = {w^<*k*> where k is Nat:
         k in card NIC(M/.(T2.w),T2.w)} by A14,A16;
        hence thesis by A48,A50,A52,A72,A73,TARSKI:def 4;
      end;
      dom T1-level (n+1) = union U1 by TREES_9:45;
      hence thesis by A21,TREES_9:45;
    end;
    dom T1-level 0 = {{}} by TREES_9:44
      .= dom T2-level 0 by TREES_9:44;
    then
A74: P[0];
A75: for n being Nat holds P[n] from NAT_1:sch 2(A74,A17);
    for p being FinSequence of NAT st p in dom T1 holds (T1 qua Function
    ).p = (T2 qua Function).p
    proof
      let p be FinSequence of NAT;
      defpred P[Nat] means $1 <= len p & p|Seg $1 in dom T1 implies
      T1.(p|Seg $1) = T2.(p|Seg $1);
A76:  p|Seg len p = p by FINSEQ_3:49;
A77:  for n being Nat st P[n] holds P[n+1]
      proof
        let n be Nat;
        assume that
A78:    P[n] and
A79:    n+1 <= len p and
A80:    p|Seg (n+1) in dom T1;
        set t1 = p|Seg n;
A81:    1 <= n+1 by NAT_1:11;
A82:    len(p|Seg(n+1)) = n+1 by A79,FINSEQ_1:17;
        then len(p|Seg(n+1)) in Seg(n+1) by A81,FINSEQ_1:1;
        then
A83:    p.(n+1) = (p|Seg(n+1)).len(p|Seg(n+1)) by A82,FUNCT_1:49;
        n+1 in dom p by A79,A81,FINSEQ_3:25;
        then
A84:    p|Seg(n+1) = t1^<*(p|Seg(n+1)).len (p|Seg(n+1))*> by A83,FINSEQ_5:10;
A85:    n <= n+1 by NAT_1:11;
        then Seg n c= Seg(n+1) by FINSEQ_1:5;
        then p|Seg n = p|Seg(n+1)|Seg n by RELAT_1:74;
        then p|Seg n is_a_prefix_of p|Seg(n+1) by TREES_1:def 1;
        then reconsider t1 as Element of dom T1 by A80,TREES_1:20;
        reconsider t2 = t1 as Element of dom T2 by A75,TREES_2:38;
A86:    succ t1 = { t1^<*k*> where k is Nat:
        k in card NIC(M/.(T1.t1),T1.t1)} by A14;
        t1^<*(p|Seg(n+1)).len (p|Seg(n+1))*> in succ t1 by A80,A84,
TREES_2:12;
        then consider k being Nat such that
A87:    t1^<*(p|Seg(n+1)).len (p|Seg(n+1))*> = t1^<*k*> and
A88:    k in card NIC(M/.(T1.t1),T1.t1) by A86;
A89:    (p|Seg(n+1)).len (p|Seg(n+1)) in card NIC(M/.(T2.t2),T2.t2) by A78,A79
,A85,A87,A88,FINSEQ_2:17,XXREAL_0:2;
        k = (p|Seg(n+1)).len (p|Seg(n+1)) by A87,FINSEQ_2:17;
        hence
        T1.(p|Seg (n+1)) = (LocSeq(NIC(M/.(T1.t1),T1.t1),S)).((p|Seg(n+1)).
        len (p|Seg(n+1))) by A14,A84,A88
          .= T2.(p|Seg (n+1)) by A16,A78,A79,A85,A84,A89,XXREAL_0:2;
      end;
A90:  P[0] by A13,A15;
      for n being Nat holds P[n] from NAT_1:sch 2(A90,A77);
      hence thesis by A76;
    end;
    hence thesis by A75,TREES_2:31,38;
  end;
end;

theorem
  for S being standard halting IC-Ins-separated
    non empty with_non-empty_values AMI-Struct over N holds ExecTree Stop S =
  TrivialInfiniteTree --> 0
proof
  set D = TrivialInfiniteTree;
  let S be standard halting IC-Ins-separated non empty
  with_non-empty_values AMI-Struct over N;
  set M = Stop S;
  set E = ExecTree M;
  defpred R[set] means E.$1 in dom M;
  defpred X[Nat] means dom E-level $1 = D-level $1;
A2: M.0 = halt S by FUNCOP_1:72;
A3: for t being Element of dom E holds card NIC(halt S,E.t) = {0}
  proof
    let t be Element of dom E;
    reconsider Et = E.t as Nat;
    NIC(halt S,Et) = {Et} by AMISTD_1:2;
    hence thesis by CARD_1:30,49;
  end;
A4: for f being Element of dom E st R[f]
  for a being Element of NAT st f^<*a*> in dom E holds R[f^<*a*>]
  proof
    let f be Element of dom E such that
A5: R[f];
A6: M/.(E.f) = M.(E.f) by A5,PARTFUN1:def 6;
    reconsider Ef = E.f as Nat;
A7: E.f = 0 by A5,TARSKI:def 1;
    then NIC(halt S,E.f) = {0} by AMISTD_1:2;
    then canonical_isomorphism_of (RelIncl order_type_of RelIncl
     NIC(M/.(E.f),E.f), RelIncl NIC(M/.(E.f),E.f))
      = 0 .--> Ef
     by A2,A7,A6,CARD_5:38;
    then
A8: canonical_isomorphism_of (RelIncl order_type_of RelIncl
 NIC(M/.(E.f),E.f), RelIncl NIC(M/.(E.f),E.f)).0
  = Ef by FUNCOP_1:72
      .= 0 by A5,TARSKI:def 1;
A9: card NIC(halt S,E.f) = {0} by A3;
    then
A10: 0 in card NIC(M/.(E.f),E.f) by A2,A7,A6,TARSKI:def 1;
A11: succ f = { f^<*k*> where k is Nat: k in card NIC(M/.(E.f)
    ,E.f) } by Def2;
A12: succ f = { f^<*0*> }
    proof
      hereby
        let s be object;
        assume s in succ f;
        then consider k being Nat such that
A13:    s = f^<*k*> and
A14:    k in card NIC(M/.(E.f),E.f) by A11;
        k = 0 by A2,A9,A7,A6,A14,TARSKI:def 1;
        hence s in { f^<*0*> } by A13,TARSKI:def 1;
      end;
      let s be object;
      assume s in { f^<*0*> };
      then s = f^<*0*> by TARSKI:def 1;
      hence thesis by A11,A10;
    end;
    let a be Element of NAT;
    assume f^<*a*> in dom E;
    then f^<*a*> in succ f by TREES_2:12;
    then f^<*a*> = f^<*0*> by A12,TARSKI:def 1;
    then E.(f^<*a*>) = (LocSeq(NIC(M/.(E.f),E.f),S)).0 by A10,Def2
      .= 0 by A10,A8,Def1;
    hence thesis by TARSKI:def 1;
  end;
  E.{} = FirstLoc(M) by Def2;
  then
A15: R[<*>NAT] by VALUED_1:33;
A16: for f being Element of dom E holds R[f] from HILBERT2:sch 1(A15,A4);
A17: for x being object st x in dom E holds (E qua Function).x = 0
  proof
    let x be object;
    assume x in dom E;
    then reconsider x as Element of dom E;
    E.x in dom M by A16;
    hence thesis by TARSKI:def 1;
  end;
A18: for n being Nat st X[n] holds X[n+1]
  proof
    let n be Nat;
    set f0 = n |-> 0;
    set f1 = (n+1) |-> 0;
A19: dom E-level (n+1) = {w where w is Element of dom E: len w = n+1} by
TREES_2:def 6;
A20: len f1 = n+1 by CARD_1:def 7;
    assume
A21: X[n];
    dom E-level (n+1) = {f1}
    proof
      hereby
        let a be object;
        assume a in dom E-level (n+1);
        then consider t1 being Element of dom E such that
A22:    a = t1 and
A23:    len t1 = n+1 by A19;
        reconsider t0 = t1|Seg n as Element of dom E by RELAT_1:59,TREES_1:20;
A24:    succ t0 = { t0^<*k*> where k is Nat:
          k in card NIC(M/.(E.t0),E.t0) } by Def2;
        E.t0 in dom M by A16;
        then
A25:    E.t0 = 0 by TARSKI:def 1;
A26:    card NIC(halt S,E.t0) = {0} & M/.(E.t0) = M.(E.t0) by A3,A16,
PARTFUN1:def 6;
        then
A27:    0 in card NIC(M/.(E.t0),E.t0) by A2,A25,TARSKI:def 1;
A28:    succ t0 = { t0^<*0*> }
        proof
          hereby
            let s be object;
            assume s in succ t0;
            then consider k being Nat such that
A29:        s = t0^<*k*> and
A30:        k in card NIC(M/.(E.t0),E.t0) by A24;
            k = 0 by A2,A25,A26,A30,TARSKI:def 1;
            hence s in { t0^<*0*> } by A29,TARSKI:def 1;
          end;
          let s be object;
          assume s in { t0^<*0*> };
          then s = t0^<*0*> by TARSKI:def 1;
          hence thesis by A24,A27;
        end;
        t1.(n+1) is Nat & t1 = t0^<*t1.(n+1)*> by A23,FINSEQ_3:55;
        then t0^<*t1.(n+1)*> in succ t0 by TREES_2:12;
        then
A31:    t0^<*t1.(n+1)*> = t0^<*0*> by A28,TARSKI:def 1;
A32:     n in NAT by ORDINAL1:def 12;
        n <= n+1 by NAT_1:11;
        then Seg n c= Seg(n+1) by FINSEQ_1:5;
        then Seg n c= dom t1 by A23,FINSEQ_1:def 3;
        then dom t0 = Seg n by RELAT_1:62;
        then dom E-level n = {w where w is Element of dom E: len w = n} & len
        t0 = n by FINSEQ_1:def 3,TREES_2:def 6,A32;
        then
A33:    t0 in dom E-level n;
A34:    dom E-level n = {f0} by A21,TREES_2:39;
        for k being Nat st 1 <= k & k <= len t1 holds t1.k = f1.k
        proof
          let k be Nat;
          assume 1 <= k & k <= len t1;
          then
A35:      k in Seg(n+1) by A23,FINSEQ_1:1;
          now
            per cases by A35,FINSEQ_2:7;
            suppose
A36:          k in Seg n;
              hence t1.k = t0.k by FUNCT_1:49
                .= f0.k by A34,A33,TARSKI:def 1
                .= 0 by A36,FUNCOP_1:7;
            end;
            suppose
              k = n+1;
              hence t1.k = 0 by A31,FINSEQ_2:17;
            end;
          end;
          hence thesis by A35,FUNCOP_1:7;
        end;
        then t1 = f1 by A20,A23,FINSEQ_1:14;
        hence a in {f1} by A22,TARSKI:def 1;
      end;
      defpred P[Nat] means $1 |-> 0 in dom E;
      let a be object;
A37:  for n being Nat st P[n] holds P[n+1]
      proof
        let n be Nat;
        assume P[n];
        then reconsider t = n |-> 0 as Element of dom E;
A38:    succ t = { t^<*k*> where k is Nat:
          k in card NIC(M/.(E.t),E.t) } by Def2;
        E.t in dom M by A16;
        then
A39:    E.t = 0 by TARSKI:def 1;
        card NIC(halt S,E.t) = {0} & M/.(E.t) = M.(E.t)
           by A3,A16,PARTFUN1:def 6;
        then 0 in card NIC(M/.(E.t),E.t) by A2,A39,TARSKI:def 1;
        then t^<*0*> in succ t by A38;
        then t^<*0*> in dom E;
        hence thesis by FINSEQ_2:60;
      end;
A40:  P[0] by TREES_1:22;
      for n being Nat holds P[n] from NAT_1:sch 2(A40,A37);
      then
A41:  f1 is Element of dom E;
      assume a in {f1};
      then a = f1 by TARSKI:def 1;
      hence thesis by A19,A20,A41;
    end;
    hence thesis by TREES_2:39;
  end;
  dom E-level 0 = {{}} by TREES_9:44
    .= D-level 0 by TREES_9:44;
  then
A42: X[0];
  for x being Nat holds X[x] from NAT_1:sch 2(A42,A18);
  then dom E = D by TREES_2:38;
  hence thesis by A17,FUNCOP_1:11;
end;