defpred S1[ Element of QC-Sub-WFF ] means ( $1 is Element of CQC-Sub-WFF implies P1[$1] );
A2: for S being Element of QC-Sub-WFF st S1[S] holds
S1[ Sub_not S]
proof
let S be Element of QC-Sub-WFF ; :: thesis: ( S1[S] implies S1[ Sub_not S] )
assume A3: S1[S] ; :: thesis: S1[ Sub_not S]
assume Sub_not S is Element of CQC-Sub-WFF ; :: thesis: P1[ Sub_not S]
then Sub_not S in CQC-Sub-WFF ;
then consider S9 being Element of QC-Sub-WFF such that
A4: Sub_not S = S9 and
A5: S9 `1 is Element of CQC-WFF ;
S9 `1 = 'not' (S `1 ) by A4, MCART_1:7;
then S `1 is Element of CQC-WFF by A5, CQC_LANG:18;
then S in CQC-Sub-WFF ;
hence P1[ Sub_not S] by A1, A3; :: thesis: verum
end;
A6: for k being Element of NAT
for P being QC-pred_symbol of k
for ll being QC-variable_list of k
for e being Element of vSUB holds S1[ Sub_P P,ll,e]
proof
let k be Element of NAT ; :: thesis: for P being QC-pred_symbol of k
for ll being QC-variable_list of k
for e being Element of vSUB holds S1[ Sub_P P,ll,e]

let P be QC-pred_symbol of k; :: thesis: for ll being QC-variable_list of k
for e being Element of vSUB holds S1[ Sub_P P,ll,e]

let ll be QC-variable_list of k; :: thesis: for e being Element of vSUB holds S1[ Sub_P P,ll,e]
let e be Element of vSUB ; :: thesis: S1[ Sub_P P,ll,e]
assume Sub_P P,ll,e is Element of CQC-Sub-WFF ; :: thesis: P1[ Sub_P P,ll,e]
then Sub_P P,ll,e in CQC-Sub-WFF ;
then A7: ex S1 being Element of QC-Sub-WFF st
( Sub_P P,ll,e = S1 & S1 `1 is Element of CQC-WFF ) ;
Sub_P P,ll,e = [(P ! ll),e] by Th9;
then A8: P ! ll is Element of CQC-WFF by A7, MCART_1:7;
then A9: { (ll . j) where j is Element of NAT : ( 1 <= j & j <= len ll & ll . j in fixed_QC-variables ) } = {} by CQC_LANG:17;
{ (ll . i) where i is Element of NAT : ( 1 <= i & i <= len ll & ll . i in free_QC-variables ) } = {} by A8, CQC_LANG:17;
then ll is CQC-variable_list of k by A9, CQC_LANG:15;
hence P1[ Sub_P P,ll,e] by A1; :: thesis: verum
end;
A10: for S1, S2 being Element of QC-Sub-WFF st S1 `2 = S2 `2 & S1[S1] & S1[S2] holds
S1[ Sub_& S1,S2]
proof
let S1, S2 be Element of QC-Sub-WFF ; :: thesis: ( S1 `2 = S2 `2 & S1[S1] & S1[S2] implies S1[ Sub_& S1,S2] )
assume that
A11: S1 `2 = S2 `2 and
A12: ( S1[S1] & S1[S2] ) ; :: thesis: S1[ Sub_& S1,S2]
assume Sub_& S1,S2 is Element of CQC-Sub-WFF ; :: thesis: P1[ Sub_& S1,S2]
then Sub_& S1,S2 in CQC-Sub-WFF ;
then consider S9 being Element of QC-Sub-WFF such that
A13: Sub_& S1,S2 = S9 and
A14: S9 `1 is Element of CQC-WFF ;
Sub_& S1,S2 = [((S1 `1 ) '&' (S2 `1 )),(S1 `2 )] by A11, Def21;
then A15: S9 `1 = (S1 `1 ) '&' (S2 `1 ) by A13, MCART_1:7;
then S2 `1 is Element of CQC-WFF by A14, CQC_LANG:19;
then A16: S2 in CQC-Sub-WFF ;
S1 `1 is Element of CQC-WFF by A14, A15, CQC_LANG:19;
then S1 in CQC-Sub-WFF ;
hence P1[ Sub_& S1,S2] by A1, A11, A12, A16; :: thesis: verum
end;
A17: for x being bound_QC-variable
for S being Element of QC-Sub-WFF
for SQ being second_Q_comp of [S,x] st [S,x] is quantifiable & S1[S] holds
S1[ Sub_All [S,x],SQ]
proof
let x be bound_QC-variable; :: thesis: for S being Element of QC-Sub-WFF
for SQ being second_Q_comp of [S,x] st [S,x] is quantifiable & S1[S] holds
S1[ Sub_All [S,x],SQ]

let S be Element of QC-Sub-WFF ; :: thesis: for SQ being second_Q_comp of [S,x] st [S,x] is quantifiable & S1[S] holds
S1[ Sub_All [S,x],SQ]

let SQ be second_Q_comp of [S,x]; :: thesis: ( [S,x] is quantifiable & S1[S] implies S1[ Sub_All [S,x],SQ] )
assume that
A18: [S,x] is quantifiable and
A19: S1[S] ; :: thesis: S1[ Sub_All [S,x],SQ]
assume Sub_All [S,x],SQ is Element of CQC-Sub-WFF ; :: thesis: P1[ Sub_All [S,x],SQ]
then Sub_All [S,x],SQ in CQC-Sub-WFF ;
then consider S9 being Element of QC-Sub-WFF such that
A20: Sub_All [S,x],SQ = S9 and
A21: S9 `1 is Element of CQC-WFF ;
A22: [S,x] `1 = S by MCART_1:7;
Sub_All [S,x],SQ = [(All ([S,x] `2 ),(([S,x] `1 ) `1 )),SQ] by A18, Def24;
then S9 `1 = All ([S,x] `2 ),(([S,x] `1 ) `1 ) by A20, MCART_1:7;
then ([S,x] `1 ) `1 is Element of CQC-WFF by A21, CQC_LANG:23;
then S in CQC-Sub-WFF by A22;
hence P1[ Sub_All [S,x],SQ] by A1, A18, A19; :: thesis: verum
end;
A23: for S being Element of QC-Sub-WFF st S is Sub_VERUM holds
S1[S] by A1;
for S being Element of QC-Sub-WFF holds S1[S] from SUBSTUT1:sch 1(A6, A23, A2, A10, A17);
hence for S being Element of CQC-Sub-WFF holds P1[S] ; :: thesis: verum