let V be Universe; :: thesis: for X being Subclass of V
for E being non empty set st X is closed_wrt_A1-A7 & E in X holds
for H, H9 being ZF-formula st Diagram (H,E) in X & Diagram (H9,E) in X holds
Diagram ((H '&' H9),E) in X

let X be Subclass of V; :: thesis: for E being non empty set st X is closed_wrt_A1-A7 & E in X holds
for H, H9 being ZF-formula st Diagram (H,E) in X & Diagram (H9,E) in X holds
Diagram ((H '&' H9),E) in X

let E be non empty set ; :: thesis: ( X is closed_wrt_A1-A7 & E in X implies for H, H9 being ZF-formula st Diagram (H,E) in X & Diagram (H9,E) in X holds
Diagram ((H '&' H9),E) in X )

assume that
A1: X is closed_wrt_A1-A7 and
A2: E in X ; :: thesis: for H, H9 being ZF-formula st Diagram (H,E) in X & Diagram (H9,E) in X holds
Diagram ((H '&' H9),E) in X

reconsider E9 = E as Element of V by A2;
let H, H9 be ZF-formula; :: thesis: ( Diagram (H,E) in X & Diagram (H9,E) in X implies Diagram ((H '&' H9),E) in X )
assume that
A3: Diagram (H,E) in X and
A4: Diagram (H9,E) in X ; :: thesis: Diagram ((H '&' H9),E) in X
set fs = code (Free H);
set fs9 = code (Free H9);
reconsider D1 = Diagram (H,E), D2 = Diagram (H9,E) as Element of V by A3, A4;
A5: Funcs (((code (Free H9)) \ (code (Free H))),E9) in X by A1, A2, Th9;
then reconsider F1 = Funcs (((code (Free H9)) \ (code (Free H))),E9) as Element of V ;
A6: Funcs (((code (Free H)) \ (code (Free H9))),E9) in X by A1, A2, Th9;
then reconsider F2 = Funcs (((code (Free H)) \ (code (Free H9))),E9) as Element of V ;
set A = { (x \/ y) where x, y is Element of V : ( x in D1 & y in F1 ) } ;
set B = { (x \/ y) where x, y is Element of V : ( x in D2 & y in F2 ) } ;
A7: X is closed_wrt_A5 by A1;
then A8: { (x \/ y) where x, y is Element of V : ( x in D2 & y in F2 ) } in X by A4, A6;
now :: thesis: for p being object st p in { (x \/ y) where x, y is Element of V : ( x in D1 & y in F1 ) } /\ { (x \/ y) where x, y is Element of V : ( x in D2 & y in F2 ) } holds
p in Diagram ((H '&' H9),E)
let p be object ; :: thesis: ( p in { (x \/ y) where x, y is Element of V : ( x in D1 & y in F1 ) } /\ { (x \/ y) where x, y is Element of V : ( x in D2 & y in F2 ) } implies p in Diagram ((H '&' H9),E) )
assume A9: p in { (x \/ y) where x, y is Element of V : ( x in D1 & y in F1 ) } /\ { (x \/ y) where x, y is Element of V : ( x in D2 & y in F2 ) } ; :: thesis: p in Diagram ((H '&' H9),E)
then p in { (x \/ y) where x, y is Element of V : ( x in D1 & y in F1 ) } by XBOOLE_0:def 4;
then consider x, y being Element of V such that
A10: p = x \/ y and
A11: x in D1 and
A12: y in F1 ;
p in { (x \/ y) where x, y is Element of V : ( x in D2 & y in F2 ) } by A9, XBOOLE_0:def 4;
then consider x9, y9 being Element of V such that
A13: p = x9 \/ y9 and
A14: x9 in D2 and
A15: y9 in F2 ;
consider g being Function of VAR,E such that
A16: x9 = (g * decode) | (code (Free H9)) and
A17: g in St (H9,E) by A14, Def4;
consider e being Function such that
A18: y = e and
A19: dom e = (code (Free H9)) \ (code (Free H)) and
A20: rng e c= E by A12, FUNCT_2:def 2;
consider f being Function of VAR,E such that
A21: x = (f * decode) | (code (Free H)) and
A22: f in St (H,E) by A11, Def4;
A23: dom ((f * decode) | (code (Free H))) = code (Free H) by Lm3;
then reconsider gg = ((f * decode) | (code (Free H))) \/ e as Function by A19, GRFUNC_1:13, XBOOLE_1:79;
rng gg = (rng ((f * decode) | (code (Free H)))) \/ (rng e) by RELAT_1:12;
then A24: rng gg c= E by A20, XBOOLE_1:8;
dom gg = (code (Free H)) \/ ((code (Free H9)) \ (code (Free H))) by A19, A23, XTUPLE_0:23;
then dom gg = (code (Free H)) \/ (code (Free H9)) by XBOOLE_1:39;
then gg in Funcs (((code (Free H)) \/ (code (Free H9))),E) by A24, FUNCT_2:def 2;
then consider ff being Function of VAR,E such that
A25: gg = (ff * decode) | ((code (Free H)) \/ (code (Free H9))) by Lm11;
now :: thesis: ( code (Free H) = dom ((ff * decode) | (code (Free H))) & dom ((f * decode) | (code (Free H))) = code (Free H) & ( for q being object st q in code (Free H) holds
((ff * decode) | (code (Free H))) . q = ((f * decode) | (code (Free H))) . q ) )
thus A26: ( code (Free H) = dom ((ff * decode) | (code (Free H))) & dom ((f * decode) | (code (Free H))) = code (Free H) ) by Lm3; :: thesis: for q being object st q in code (Free H) holds
((ff * decode) | (code (Free H))) . q = ((f * decode) | (code (Free H))) . q

let q be object ; :: thesis: ( q in code (Free H) implies ((ff * decode) | (code (Free H))) . q = ((f * decode) | (code (Free H))) . q )
assume A27: q in code (Free H) ; :: thesis: ((ff * decode) | (code (Free H))) . q = ((f * decode) | (code (Free H))) . q
(ff * decode) | ((code (Free H)) \/ (code (Free H9))) = ((ff * decode) | (code (Free H))) \/ ((ff * decode) | (code (Free H9))) by RELAT_1:78;
hence ((ff * decode) | (code (Free H))) . q = ((ff * decode) | ((code (Free H)) \/ (code (Free H9)))) . q by A26, A27, GRFUNC_1:15
.= ((f * decode) | (code (Free H))) . q by A25, A26, A27, GRFUNC_1:15 ;
:: thesis: verum
end;
then A28: ff in St (H,E) by A22, Lm10, FUNCT_1:2;
now :: thesis: ( code (Free H9) = dom ((ff * decode) | (code (Free H9))) & dom ((g * decode) | (code (Free H9))) = code (Free H9) & ( for q being object st q in code (Free H9) holds
((ff * decode) | (code (Free H9))) . q = ((g * decode) | (code (Free H9))) . q ) )
thus A29: ( code (Free H9) = dom ((ff * decode) | (code (Free H9))) & dom ((g * decode) | (code (Free H9))) = code (Free H9) ) by Lm3; :: thesis: for q being object st q in code (Free H9) holds
((ff * decode) | (code (Free H9))) . q = ((g * decode) | (code (Free H9))) . q

let q be object ; :: thesis: ( q in code (Free H9) implies ((ff * decode) | (code (Free H9))) . q = ((g * decode) | (code (Free H9))) . q )
assume A30: q in code (Free H9) ; :: thesis: ((ff * decode) | (code (Free H9))) . q = ((g * decode) | (code (Free H9))) . q
(ff * decode) | ((code (Free H)) \/ (code (Free H9))) = ((ff * decode) | (code (Free H))) \/ ((ff * decode) | (code (Free H9))) by RELAT_1:78;
hence ((ff * decode) | (code (Free H9))) . q = ((ff * decode) | ((code (Free H)) \/ (code (Free H9)))) . q by A29, A30, GRFUNC_1:15
.= ((g * decode) | (code (Free H9))) . q by A10, A13, A15, A21, A16, A18, A25, A29, A30, GRFUNC_1:15 ;
:: thesis: verum
end;
then ff in St (H9,E) by A17, Lm10, FUNCT_1:2;
then A31: ff in St ((H '&' H9),E) by A28, ZF_MODEL:5;
p = (ff * decode) | (code ((Free H) \/ (Free H9))) by A10, A21, A18, A25, RELAT_1:120
.= (ff * decode) | (code (Free (H '&' H9))) by ZF_LANG1:61 ;
hence p in Diagram ((H '&' H9),E) by A31, Def4; :: thesis: verum
end;
then A32: { (x \/ y) where x, y is Element of V : ( x in D1 & y in F1 ) } /\ { (x \/ y) where x, y is Element of V : ( x in D2 & y in F2 ) } c= Diagram ((H '&' H9),E) ;
Diagram ((H '&' H9),E) c= { (x \/ y) where x, y is Element of V : ( x in D1 & y in F1 ) } /\ { (x \/ y) where x, y is Element of V : ( x in D2 & y in F2 ) }
proof
let p be object ; :: according to TARSKI:def 3 :: thesis: ( not p in Diagram ((H '&' H9),E) or p in { (x \/ y) where x, y is Element of V : ( x in D1 & y in F1 ) } /\ { (x \/ y) where x, y is Element of V : ( x in D2 & y in F2 ) } )
assume p in Diagram ((H '&' H9),E) ; :: thesis: p in { (x \/ y) where x, y is Element of V : ( x in D1 & y in F1 ) } /\ { (x \/ y) where x, y is Element of V : ( x in D2 & y in F2 ) }
then consider f being Function of VAR,E such that
A33: p = (f * decode) | (code (Free (H '&' H9))) and
A34: f in St ((H '&' H9),E) by Def4;
f in St (H9,E) by A34, ZF_MODEL:5;
then A35: (f * decode) | (code (Free H9)) in D2 by Def4;
then reconsider z = (f * decode) | (code (Free H9)) as Element of V by A4, Th1;
(f * decode) | ((code (Free H)) \ (code (Free H9))) is Function of ((code (Free H)) \ (code (Free H9))),E by FUNCT_2:32;
then A36: (f * decode) | ((code (Free H)) \ (code (Free H9))) in F2 by FUNCT_2:8;
then reconsider t = (f * decode) | ((code (Free H)) \ (code (Free H9))) as Element of V by A6, Th1;
A37: Free (H '&' H9) = (Free H) \/ (Free H9) by ZF_LANG1:61;
then p = (f * decode) | ((code (Free H9)) \/ (code (Free H))) by A33, RELAT_1:120
.= (f * decode) | ((code (Free H9)) \/ ((code (Free H)) \ (code (Free H9)))) by XBOOLE_1:39
.= ((f * decode) | (code (Free H9))) \/ ((f * decode) | ((code (Free H)) \ (code (Free H9)))) by RELAT_1:78 ;
then p = z \/ t ;
then A38: p in { (x \/ y) where x, y is Element of V : ( x in D2 & y in F2 ) } by A35, A36;
f in St (H,E) by A34, ZF_MODEL:5;
then A39: (f * decode) | (code (Free H)) in D1 by Def4;
then reconsider x = (f * decode) | (code (Free H)) as Element of V by A3, Th1;
(f * decode) | ((code (Free H9)) \ (code (Free H))) is Function of ((code (Free H9)) \ (code (Free H))),E by FUNCT_2:32;
then A40: (f * decode) | ((code (Free H9)) \ (code (Free H))) in F1 by FUNCT_2:8;
then reconsider y = (f * decode) | ((code (Free H9)) \ (code (Free H))) as Element of V by A5, Th1;
p = (f * decode) | ((code (Free H)) \/ (code (Free H9))) by A33, A37, RELAT_1:120
.= (f * decode) | ((code (Free H)) \/ ((code (Free H9)) \ (code (Free H)))) by XBOOLE_1:39
.= ((f * decode) | (code (Free H))) \/ ((f * decode) | ((code (Free H9)) \ (code (Free H)))) by RELAT_1:78 ;
then p = x \/ y ;
then p in { (x \/ y) where x, y is Element of V : ( x in D1 & y in F1 ) } by A39, A40;
hence p in { (x \/ y) where x, y is Element of V : ( x in D1 & y in F1 ) } /\ { (x \/ y) where x, y is Element of V : ( x in D2 & y in F2 ) } by A38, XBOOLE_0:def 4; :: thesis: verum
end;
then A41: { (x \/ y) where x, y is Element of V : ( x in D1 & y in F1 ) } /\ { (x \/ y) where x, y is Element of V : ( x in D2 & y in F2 ) } = Diagram ((H '&' H9),E) by A32;
{ (x \/ y) where x, y is Element of V : ( x in D1 & y in F1 ) } in X by A3, A5, A7;
hence Diagram ((H '&' H9),E) in X by A1, A8, A41, Th5; :: thesis: verum