Copyright (c) 1990 Association of Mizar Users
environ vocabulary ORDINAL2, ORDINAL1, FUNCT_1, TARSKI, RELAT_1, BOOLE, FINSEQ_1, ORDINAL3, CLASSES2, CLASSES1, CARD_1, ORDINAL4; notation TARSKI, XBOOLE_0, ZFMISC_1, SUBSET_1, RELAT_1, FUNCT_1, ORDINAL1, ORDINAL2, ORDINAL3, CARD_1, CLASSES1, CLASSES2; constructors WELLORD2, ORDINAL3, CARD_1, CLASSES1, CLASSES2, XBOOLE_0; clusters FUNCT_1, ORDINAL1, ORDINAL2, ORDINAL3, CLASSES2, ARYTM_3, CARD_1, ZFMISC_1, XBOOLE_0; requirements SUBSET, BOOLE; definitions TARSKI, ORDINAL2, XBOOLE_0; theorems ZFMISC_1, FUNCT_1, GRFUNC_1, ORDINAL1, ORDINAL2, ORDINAL3, CARD_2, CLASSES2, RELAT_1, CLASSES1, XBOOLE_0, XBOOLE_1; schemes ORDINAL1, ORDINAL2, PARTFUN1; begin reserve phi,fi,psi for Ordinal-Sequence, A,A1,B,C,D for Ordinal, f,g for Function, X for set, x,y,z for set; definition let L be Ordinal-Sequence; cluster last L -> ordinal; coherence proof last L = L.(union dom L) by ORDINAL2:def 1; hence thesis; end; end; theorem dom fi = succ A implies last fi is_limes_of fi & lim fi = last fi proof assume A1: dom fi = succ A; then A2: fi.A is Ordinal & last fi = fi.A by ORDINAL2:7; thus last fi is_limes_of fi proof per cases; case A3: last fi = {}; take A; thus A in dom fi by A1,ORDINAL1:10; let B; assume A4: A c= B & B in dom fi; then B c= A by A1,ORDINAL1:34; hence fi.B = {} by A2,A3,A4,XBOOLE_0:def 10; case last fi <> {}; let B,C such that A5: B in last fi & last fi in C; take A; thus A in dom fi by A1,ORDINAL1:10; let D; assume A6: A c= D & D in dom fi; then D c= A by A1,ORDINAL1:34; hence thesis by A2,A5,A6,XBOOLE_0:def 10; end; hence lim fi = last fi by ORDINAL2:def 14; end; definition let fi,psi be T-Sequence; func fi^psi -> T-Sequence means: Def1: dom it = (dom fi)+^(dom psi) & (for A st A in dom fi holds it.A = fi.A) & (for A st A in dom psi holds it.((dom fi)+^A) = psi.A); existence proof deffunc F(Ordinal) = fi.$1; deffunc G(Ordinal) = psi.(($1)-^dom fi); defpred P[set] means $1 in dom fi; consider f such that A1: dom f = (dom fi)+^(dom psi) and A2: for x being set st x in (dom fi)+^(dom psi) holds (P[x] implies f.x = F(x)) & (not P[x] implies f.x = G(x)) from LambdaC; reconsider f as T-Sequence by A1,ORDINAL1:def 7; take f; thus dom f = (dom fi)+^(dom psi) by A1; thus for A st A in dom fi holds f.A = fi.A proof let A such that A3: A in dom fi; dom fi c= dom f by A1,ORDINAL3:27; hence thesis by A1,A2,A3; end; let A; assume A in dom psi; then A4: (dom fi)+^A in dom f by A1,ORDINAL2:49; dom fi c= (dom fi)+^A by ORDINAL3:27; then not (dom fi)+^A in dom fi by ORDINAL1:7; then f.((dom fi)+^A) = psi.((((dom fi)+^A))-^dom fi) & ((dom fi)+^A)-^dom fi = A by A1,A2,A4,ORDINAL3:65; hence thesis; end; uniqueness proof let f1,f2 be T-Sequence such that A5: dom f1 = (dom fi)+^(dom psi) & (for A st A in dom fi holds f1.A = fi.A) & (for A st A in dom psi holds f1.((dom fi)+^A) = psi.A) and A6: dom f2 = (dom fi)+^(dom psi) & (for A st A in dom fi holds f2.A = fi.A) & (for A st A in dom psi holds f2.((dom fi)+^A) = psi.A); now let x; assume A7: x in (dom fi)+^(dom psi); then reconsider A = x as Ordinal by ORDINAL1:23; now per cases; suppose x in dom fi; then f1.A = fi.A & f2.A = fi.A by A5,A6; hence f1.x = f2.x; suppose not x in dom fi; then dom fi c= A by ORDINAL1:26; then A8: (dom fi)+^(A-^dom fi) = A by ORDINAL3:def 6; then A-^dom fi in dom psi by A7,ORDINAL3:25; then f1.A = psi.(A-^dom fi) & f2.A = psi.(A-^dom fi) by A5,A6,A8; hence f1.x = f2.x; end; hence f1.x = f2.x; end; hence thesis by A5,A6,FUNCT_1:9; end; end; definition let fi,psi; cluster fi^psi -> Ordinal-yielding; coherence proof set f = fi^psi; A1: dom f = dom fi +^ dom psi by Def1; consider A1 being Ordinal such that A2: rng fi c= A1 by ORDINAL2:def 8; consider A2 being Ordinal such that A3: rng psi c= A2 by ORDINAL2:def 8; rng f c= A1+^A2 proof let y; assume y in rng f; then consider x such that A4: x in dom f & y = f.x by FUNCT_1:def 5; reconsider x as Ordinal by A4,ORDINAL1:23; A5: A1 c= A1+^A2 & A2 c= A1+^A2 by ORDINAL3:27; now per cases; suppose x in dom fi; then y = fi.x & fi.x in rng fi by A4,Def1,FUNCT_1:def 5; then y in A1 by A2; hence thesis by A5; suppose not x in dom fi; then dom fi c= x by ORDINAL1:26; then A6: (dom fi)+^(x-^dom fi) = x by ORDINAL3:def 6; then A7: x-^dom fi in dom psi by A1,A4,ORDINAL3:25; then y = psi.(x-^dom fi) by A4,A6,Def1; then y in rng psi by A7,FUNCT_1:def 5; then y in A2 by A3; hence thesis by A5; end; hence thesis; end; hence f is Ordinal-yielding by ORDINAL2:def 8; end; end; canceled; theorem Th3: A is_limes_of psi implies A is_limes_of fi^psi proof assume A1: A = {} & (ex B st B in dom psi & for C st B c= C & C in dom psi holds psi.C = {}) or A <> {} & for B,C st B in A & A in C ex D st D in dom psi & for E being Ordinal st D c= E & E in dom psi holds B in psi.E & psi.E in C; A2: dom(fi^psi) = (dom fi)+^(dom psi) by Def1; per cases; case A = {}; then consider B such that A3: B in dom psi & for C st B c= C & C in dom psi holds psi.C = {} by A1; take B1 = (dom fi)+^B; thus B1 in dom(fi^psi) by A2,A3,ORDINAL2:49; let C; assume A4: B1 c= C & C in dom(fi^psi); then A5: C = B1+^(C-^B1) by ORDINAL3:def 6 .= (dom fi)+^(B+^(C-^B1)) by ORDINAL3:33; then B c= B+^(C-^B1) & B+^(C-^B1) in dom psi by A2,A4,ORDINAL3:25,27; then (fi^psi).C = psi.(B+^(C-^B1)) & psi.(B+^(C-^B1)) = {} by A3,A5,Def1 ; hence thesis; case A <> {}; let B,C; assume B in A & A in C; then consider D such that A6: D in dom psi and A7: for E being Ordinal st D c= E & E in dom psi holds B in psi.E & psi.E in C by A1; take D1 = (dom fi)+^D; thus D1 in dom(fi^psi) by A2,A6,ORDINAL2:49; let E be Ordinal; assume A8: D1 c= E & E in dom(fi^psi); then A9: E = D1+^(E-^D1) by ORDINAL3:def 6 .= (dom fi)+^(D+^(E-^D1)) by ORDINAL3:33; then D c= D+^(E-^D1) & D+^(E-^D1) in dom psi by A2,A8,ORDINAL3:25,27; then (fi^psi).E = psi.(D+^(E-^D1)) & B in psi.(D+^(E-^D1)) & psi.(D+^(E-^D1)) in C by A7,A9,Def1; hence thesis; end; theorem A is_limes_of fi implies B+^A is_limes_of B+^fi proof assume A1: A = {} & (ex B st B in dom fi & for C st B c= C & C in dom fi holds fi.C = {}) or A <> {} & for B,C st B in A & A in C ex D st D in dom fi & for E being Ordinal st D c= E & E in dom fi holds B in fi.E & fi.E in C; A2: dom fi = dom(B+^fi) by ORDINAL3:def 2; per cases; case A3: B+^A = {}; then consider A1 such that A4: A1 in dom fi & for C st A1 c= C & C in dom fi holds fi.C = {} by A1,ORDINAL3:29; take A1; thus A1 in dom(B+^fi) by A4,ORDINAL3:def 2; let C; assume A1 c= C & C in dom(B+^fi); then (B+^fi).C = B+^(fi.C) & fi.C = {} & {} = {} by A2,A4,ORDINAL3:def 2; hence (B+^fi).C = {} by A3,ORDINAL3:29; case B+^A <> {}; now per cases; suppose A5: A = {}; then consider A1 such that A6: A1 in dom fi & for C st A1 c= C & C in dom fi holds fi.C = {} by A1; let B1,B2 be Ordinal such that A7: B1 in B+^A & B+^A in B2; take A1; thus A1 in dom(B+^fi) by A6,ORDINAL3:def 2; let C; assume A1 c= C & C in dom(B+^fi); then (B+^fi).C = B+^(fi.C) & fi.C = {} & {} = {} by A2,A6,ORDINAL3:def 2; hence B1 in (B+^fi).C & (B+^fi).C in B2 by A5,A7; suppose A8: A <> {}; let B1,B2 be Ordinal; assume B1 in B+^A & B+^A in B2; then A9: B1-^B in A & A in B2-^B & B+^A c= B2 by A8,ORDINAL1:def 2,ORDINAL3:73,74; then consider A1 such that A10: A1 in dom fi & for C st A1 c= C & C in dom fi holds B1-^B in fi.C & fi.C in B2-^B by A1; take A1; thus A1 in dom(B+^fi) by A10,ORDINAL3:def 2; B c= B+^A by ORDINAL3:27; then A11: B c= B2 & B1 c= B+^(B1-^B) by A9,ORDINAL3:75,XBOOLE_1:1; let C; assume A12: A1 c= C & C in dom(B+^fi); reconsider E = fi.C as Ordinal; A13: (B+^fi).C = B+^(fi.C) & B1-^B in E & E in B2-^B & E = E & B+^(B2-^B) = B2 by A2,A10,A11,A12,ORDINAL3:def 2,def 6; then B+^(B1-^B) in B+^E by ORDINAL2:49; hence B1 in (B+^fi).C & (B+^fi).C in B2 by A11,A13,ORDINAL1:22,ORDINAL2 :49; end; hence for A1,C st A1 in B+^A & B+^A in C ex D st D in dom(B+^fi) & for E being Ordinal st D c= E & E in dom(B+^fi) holds A1 in (B+^fi).E & (B+^fi).E in C; end; Lm1: A is_limes_of fi implies dom fi <> {} proof assume A1: A = {} & (ex B st B in dom fi & for C st B c= C & C in dom fi holds fi.C = {}) or A <> {} & for B,C st B in A & A in C ex D st D in dom fi & for E being Ordinal st D c= E & E in dom fi holds B in fi.E & fi.E in C; now per cases; suppose A = {}; hence thesis by A1; suppose A <> {}; then {} in A & A in succ A by ORDINAL1:10,ORDINAL3:10; then ex B st B in dom fi & for C st B c= C & C in dom fi holds {} in fi.C & fi.C in succ A by A1; hence thesis; end; hence thesis; end; theorem Th5: A is_limes_of fi implies A*^B is_limes_of fi*^B proof assume A1: A is_limes_of fi; then A2: dom fi = dom(fi*^B) & dom fi <> {} by Lm1,ORDINAL3:def 5; per cases; case A*^B = {}; then A3: B = {} or A = {} by ORDINAL3:34; now per cases; suppose A4: B = {}; consider x being Element of dom fi; reconsider x as Ordinal; take A1 = x; thus A1 in dom(fi*^B) by A2; let C; assume A1 c= C & C in dom(fi*^B); hence (fi*^B).C = (fi.C)*^B by A2,ORDINAL3:def 5 .= {} by A4,ORDINAL2:55; suppose B <> {}; then consider A1 such that A5: A1 in dom fi & for C st A1 c= C & C in dom fi holds fi.C = {} by A1,A3,ORDINAL2:def 13; take A1; thus A1 in dom(fi*^B) by A5,ORDINAL3:def 5; let C; assume A1 c= C & C in dom(fi*^B); then (fi*^B).C = (fi.C)*^B & fi.C = {} & {} = {} by A2,A5,ORDINAL3:def 5; hence (fi*^B).C = {} by ORDINAL2:52; end; hence ex A1 st A1 in dom(fi*^B) & for C st A1 c= C & C in dom(fi*^B) holds (fi*^B).C = {}; case A*^B <> {}; then A6: A <> {} & B <> {} by ORDINAL2:52,55; let B1,B2 be Ordinal such that A7: B1 in A*^B & A*^B in B2; A8: now given A1 such that A9: A = succ A1; A1 in A & A in succ A by A9,ORDINAL1:10; then consider D such that A10: D in dom fi & for C st D c= C & C in dom fi holds A1 in fi.C & fi.C in succ A by A1, ORDINAL2:def 13; take D; thus D in dom(fi*^B) by A10,ORDINAL3:def 5; let C; assume A11: D c= C & C in dom(fi*^B); reconsider E = fi.C as Ordinal; A12: A1 in E & E in succ A & (fi*^B).C = E*^B by A2,A10,A11,ORDINAL3:def 5; then A c= E & E c= A by A9,ORDINAL1:33,34; hence B1 in (fi*^B).C & (fi*^B).C in B2 by A7,A12,XBOOLE_0:def 10; end; now assume not ex A1 st A = succ A1; then A is_limit_ordinal by ORDINAL1:42; then consider C such that A13: C in A & B1 in C*^B by A7,ORDINAL3:49; A in succ A by ORDINAL1:10; then consider D such that A14: D in dom fi & for A1 st D c= A1 & A1 in dom fi holds C in fi.A1 & fi.A1 in succ A by A1,A13,ORDINAL2:def 13; take D; thus D in dom(fi*^B) by A14,ORDINAL3:def 5; let A1; assume A15: D c= A1 & A1 in dom(fi*^B); reconsider E = fi.A1 as Ordinal; C in fi.A1 & fi.A1 in succ A by A2,A14,A15; then C*^B in E*^B & E c= A by A6,ORDINAL1:34,ORDINAL2:57; then B1 in E*^B & E*^B c= A*^B & E = E & (fi*^B).A1 = (fi.A1)*^B by A2,A13,A15,ORDINAL1:19,ORDINAL2:58,ORDINAL3:def 5; hence B1 in (fi*^B).A1 & (fi*^B).A1 in B2 by A7,ORDINAL1:22; end; hence thesis by A8; end; theorem Th6: dom fi = dom psi & B is_limes_of fi & C is_limes_of psi & ((for A st A in dom fi holds fi.A c= psi.A) or (for A st A in dom fi holds fi.A in psi.A)) implies B c= C proof assume that A1: dom fi = dom psi and A2: B = {} & (ex A1 st A1 in dom fi & for C st A1 c= C & C in dom fi holds fi.C = {}) or B <> {} & for A1,C st A1 in B & B in C ex D st D in dom fi & for E being Ordinal st D c= E & E in dom fi holds A1 in fi.E & fi.E in C and A3: C = {} & (ex B st B in dom psi & for A1 st B c= A1 & A1 in dom psi holds psi.A1 = {}) or C <> {} & for B,A1 st B in C & C in A1 ex D st D in dom psi & for E being Ordinal st D c= E & E in dom psi holds B in psi.E & psi.E in A1 and A4: (for A st A in dom fi holds fi.A c= psi.A) or (for A st A in dom fi holds fi.A in psi.A); A5: now let A; assume A6: A in dom fi; reconsider A1 = fi.A, A2 = psi.A as Ordinal; A1 c= A2 or A1 in A2 by A4,A6; hence fi.A c= psi.A by ORDINAL1:def 2; end; now per cases; suppose B = {} & C = {}; hence thesis; suppose B = {} & C <> {}; then B in C by ORDINAL3:10; hence thesis by ORDINAL1:def 2; suppose A7: B <> {} & C = {}; then consider A1 such that A8: A1 in dom psi & for A st A1 c= A & A in dom psi holds psi.A = {} by A3; {} in B & B in succ B by A7,ORDINAL1:10,ORDINAL3:10; then consider A2 being Ordinal such that A9: A2 in dom fi & for A st A2 c= A & A in dom fi holds {} in fi.A & fi.A in succ B by A2; A1 c= A1 \/ A2 & A2 c= A1 \/ A2 & (A1 \/ A2 = A1 or A1 \/ A2 = A2) by ORDINAL3:15,XBOOLE_1:7; then psi.(A1 \/ A2) = {} & {} in fi.(A1 \/ A2) & fi.(A1 \/ A2) c= psi.(A1 \/ A2) by A1,A5,A8,A9; hence thesis; suppose A10: B <> {} & C <> {}; assume not B c= C; then C in B & B in succ B by ORDINAL1:10,26; then consider A1 such that A11: A1 in dom fi & for A st A1 c= A & A in dom fi holds C in fi.A & fi.A in succ B by A2; {} in C & C in succ C by A10,ORDINAL1:10,ORDINAL3:10; then consider A2 being Ordinal such that A12: A2 in dom psi & for A st A2 c= A & A in dom psi holds {} in psi.A & psi.A in succ C by A3; A1 c= A1 \/ A2 & A2 c= A1 \/ A2 & (A1 \/ A2 = A1 or A1 \/ A2 = A2) by ORDINAL3:15,XBOOLE_1:7; then A13: psi.(A1 \/ A2) in succ C & C in fi.(A1 \/ A2) & A1 \/ A2 in dom psi & fi.(A1 \/ A2) c= psi.(A1 \/ A2) by A1,A5,A11,A12; reconsider A3 = psi.(A1 \/ A2) as Ordinal; A3 c= C & C in A3 by A13,ORDINAL1:34; hence contradiction by ORDINAL1:7; end; hence thesis; end; reserve f1,f2 for Ordinal-Sequence; theorem dom f1 = dom fi & dom fi = dom f2 & A is_limes_of f1 & A is_limes_of f2 & (for A st A in dom fi holds f1.A c= fi.A & fi.A c= f2.A) implies A is_limes_of fi proof assume that A1: dom f1 = dom fi & dom fi = dom f2 and A2: A = {} & (ex B st B in dom f1 & for C st B c= C & C in dom f1 holds f1.C = {}) or A <> {} & for B,C st B in A & A in C ex D st D in dom f1 & for E being Ordinal st D c= E & E in dom f1 holds B in f1.E & f1.E in C and A3: A = {} & (ex B st B in dom f2 & for C st B c= C & C in dom f2 holds f2.C = {}) or A <> {} & for B,C st B in A & A in C ex D st D in dom f2 & for E being Ordinal st D c= E & E in dom f2 holds B in f2.E & f2.E in C and A4: for A st A in dom fi holds f1.A c= fi.A & fi.A c= f2.A; per cases; case A = {}; then consider B being Ordinal such that A5: B in dom f2 & for C st B c= C & C in dom f2 holds f2.C = {} by A3; take B; thus B in dom fi by A1,A5; let C; assume B c= C & C in dom fi; then f2.C = {} & fi.C c= f2.C by A1,A4,A5; hence fi.C = {} by XBOOLE_1:3; case A <> {}; let B,C; assume A6: B in A & A in C; then consider D1 being Ordinal such that A7: D1 in dom f1 & for A1 st D1 c= A1 & A1 in dom f1 holds B in f1.A1 & f1.A1 in C by A2; consider D2 being Ordinal such that A8: D2 in dom f2 & for A1 st D2 c= A1 & A1 in dom f2 holds B in f2.A1 & f2.A1 in C by A3,A6; take D = D1 \/ D2; thus D in dom fi by A1,A7,A8,ORDINAL3:15; let A1; assume A9: D c= A1 & A1 in dom fi; reconsider B1 = fi.A1, B2 = f2.A1 as Ordinal; D1 c= D & D2 c= D by XBOOLE_1:7; then D1 c= A1 & D2 c= A1 by A9,XBOOLE_1:1; then B in f1.A1 & f1.A1 c= fi.A1 & B1 c= B2 & B2 in C by A1,A4,A7,A8,A9; hence thesis by ORDINAL1:22; end; theorem Th8: dom fi <> {} & dom fi is_limit_ordinal & fi is increasing implies sup fi is_limes_of fi & lim fi = sup fi proof assume that A1: dom fi <> {} & dom fi is_limit_ordinal and A2: A in B & B in dom fi implies fi.A in fi.B; A3: sup fi = sup rng fi by ORDINAL2:35; A4: {} in dom fi by A1,ORDINAL3:10; reconsider x = fi.{} as Ordinal; A5: x in rng fi by A4,FUNCT_1:def 5; thus sup fi is_limes_of fi proof per cases; case sup fi = {}; hence thesis by A3,A5,ORDINAL2:27; case sup fi <> {}; let A,B; assume A6: A in sup fi & sup fi in B; then consider C such that A7: C in rng fi & A c= C by A3,ORDINAL2:29; consider x such that A8: x in dom fi & C = fi.x by A7,FUNCT_1:def 5; reconsider x as Ordinal by A8,ORDINAL1:23; take M = succ x; thus M in dom fi by A1,A8,ORDINAL1:41; let D; assume A9: M c= D & D in dom fi; reconsider E = fi.D as Ordinal; x in M by ORDINAL1:10; then C in E by A2,A8,A9; hence A in fi.D by A7,ORDINAL1:22; fi.D in rng fi by A9,FUNCT_1:def 5; then E in sup fi by A3,ORDINAL2:27; hence thesis by A6,ORDINAL1:19; end; hence lim fi = sup fi by ORDINAL2:def 14; end; theorem Th9: fi is increasing & A c= B & B in dom fi implies fi.A c= fi.B proof assume that A1: for A,B st A in B & B in dom fi holds fi.A in fi.B and A2: A c= B & B in dom fi; reconsider C = fi.B as Ordinal; now per cases; suppose A = B; hence thesis; suppose A <> B; then A c< B by A2,XBOOLE_0:def 8; then A in B by ORDINAL1:21; then fi.A in C by A1,A2; hence thesis by ORDINAL1:def 2; end; hence thesis; end; theorem Th10: fi is increasing & A in dom fi implies A c= fi.A proof assume that A1: for A,B st A in B & B in dom fi holds fi.A in fi.B and A2: A in dom fi & not A c= fi.A; defpred P[set] means $1 in dom fi & not $1 c= fi.$1; A3: ex A st P[A] by A2; consider A such that A4: P[A] and A5: for B st P[B] holds A c= B from Ordinal_Min(A3); reconsider B = fi.A as Ordinal; A6: B in A by A4,ORDINAL1:26; then fi.B in B by A1,A4; then B in dom fi & not B c= fi.B by A4,A6,ORDINAL1:7,19; hence contradiction by A4,A5; end; theorem Th11: phi is increasing implies phi"A is Ordinal proof assume A1: for A,B st A in B & B in dom phi holds phi.A in phi.B; now let X; assume X in phi"A; then A2: X in dom phi & phi.X in A by FUNCT_1:def 13; hence X is Ordinal by ORDINAL1:23; reconsider B = X as Ordinal by A2,ORDINAL1:23; thus X c= phi"A proof let x; assume A3: x in X; then A4: x in B; then reconsider C = x, D = phi.B as Ordinal by ORDINAL1:23; A5: C in dom phi by A2,A4,ORDINAL1:19; reconsider E = phi.C as Ordinal; E in D by A1,A2,A3; then phi.x in A by A2,ORDINAL1:19; hence thesis by A5,FUNCT_1:def 13; end; end; hence thesis by ORDINAL1:31; end; theorem Th12: f1 is increasing implies f2*f1 is Ordinal-Sequence proof assume A1: f1 is increasing; dom(f2*f1) = f1"dom f2 by RELAT_1:182; then dom(f2*f1) is Ordinal by A1,Th11; then reconsider f = f2*f1 as T-Sequence by ORDINAL1:def 7; consider A such that A2: rng f2 c= A by ORDINAL2:def 8; rng f c= rng f2 by RELAT_1:45; then rng f c= A by A2,XBOOLE_1:1; hence thesis by ORDINAL2:def 8; end; theorem f1 is increasing & f2 is increasing implies ex phi st phi = f1*f2 & phi is increasing proof assume A1: f1 is increasing & f2 is increasing; then reconsider f = f1*f2 as Ordinal-Sequence by Th12; take f; thus f = f1*f2; let A,B; assume A2: A in B & B in dom f; then A3: A in dom f by ORDINAL1:19; A4: dom f c= dom f2 by RELAT_1:44; reconsider A1 = f2.A, B1 = f2.B as Ordinal; A1 in B1 & B1 in dom f1 by A1,A2,A4,FUNCT_1:21,ORDINAL2:def 16; then f.A = f1.A1 & f.B = f1.B1 & f1.A1 in f1.B1 by A1,A2,A3,FUNCT_1:22, ORDINAL2:def 16; hence thesis; end; theorem Th14: f1 is increasing & A is_limes_of f2 & sup rng f1 = dom f2 & fi = f2*f1 implies A is_limes_of fi proof assume that A1: f1 is increasing and A2: A = {} & (ex B st B in dom f2 & for C st B c= C & C in dom f2 holds f2.C = {}) or A <> {} & for B,C st B in A & A in C ex D st D in dom f2 & for E being Ordinal st D c= E & E in dom f2 holds B in f2.E & f2.E in C and A3: sup rng f1 = dom f2 & fi = f2*f1; per cases; case A = {}; then consider B such that A4: B in dom f2 & for C st B c= C & C in dom f2 holds f2.C = {} by A2; consider B1 being Ordinal such that A5: B1 in rng f1 & B c= B1 by A3,A4,ORDINAL2:29; consider x such that A6: x in dom f1 & B1 = f1.x by A5,FUNCT_1:def 5; reconsider x as Ordinal by A6,ORDINAL1:23; take x; B1 in dom f2 by A3,A5,ORDINAL2:27; hence x in dom fi by A3,A6,FUNCT_1:21; let C such that A7: x c= C & C in dom fi; A8: dom fi c= dom f1 by A3,RELAT_1:44; reconsider C1 = f1.C as Ordinal; B1 c= C1 by A1,A6,A7,A8,Th9; then A9: B c= C1 by A5,XBOOLE_1:1; C1 in rng f1 by A7,A8,FUNCT_1:def 5; then C1 in dom f2 by A3,ORDINAL2:27; then f2.C1 = {} by A4,A9; hence thesis by A3,A7,FUNCT_1:22; case A <> {}; let B,C; assume B in A & A in C; then consider D such that A10: D in dom f2 & for A1 st D c= A1 & A1 in dom f2 holds B in f2.A1 & f2.A1 in C by A2; consider B1 being Ordinal such that A11: B1 in rng f1 & D c= B1 by A3,A10,ORDINAL2:29; consider x such that A12: x in dom f1 & B1 = f1.x by A11,FUNCT_1:def 5; reconsider x as Ordinal by A12,ORDINAL1:23; take x; B1 in dom f2 by A3,A11,ORDINAL2:27; hence x in dom fi by A3,A12,FUNCT_1:21; let E be Ordinal such that A13: x c= E & E in dom fi; A14: dom fi c= dom f1 by A3,RELAT_1:44; reconsider E1 = f1.E as Ordinal; B1 c= E1 by A1,A12,A13,A14,Th9; then A15: D c= E1 by A11,XBOOLE_1:1; E1 in rng f1 by A13,A14,FUNCT_1:def 5; then E1 in dom f2 by A3,ORDINAL2:27; then B in f2.E1 & f2.E1 in C by A10,A15; hence thesis by A3,A13,FUNCT_1:22; end; theorem Th15: phi is increasing implies phi|A is increasing proof assume A1: for A,B st A in B & B in dom phi holds phi.A in phi.B; let B,C such that A2: B in C & C in dom (phi|A); dom (phi|A) c= dom phi by FUNCT_1:76; then B in dom (phi|A) & C in dom phi by A2,ORDINAL1:19; then phi.B in phi.C & phi.B = (phi|A).B & phi.C = (phi|A).C by A1,A2, FUNCT_1:70; hence thesis; end; theorem Th16: phi is increasing & dom phi is_limit_ordinal implies sup phi is_limit_ordinal proof assume A1: phi is increasing & dom phi is_limit_ordinal; A2: sup phi = sup rng phi by ORDINAL2:35; now let A; assume A in sup phi; then consider B such that A3: B in rng phi & A c= B by A2,ORDINAL2:29; consider x such that A4: x in dom phi & B = phi.x by A3,FUNCT_1:def 5; reconsider x as Ordinal by A4,ORDINAL1:23; A5: x in succ x & succ x in dom phi by A1,A4,ORDINAL1:10,41; reconsider C = phi.succ x as Ordinal; B in C & C in rng phi by A1,A4,A5,FUNCT_1:def 5,ORDINAL2:def 16; then succ B c= C & C in sup phi by A2,ORDINAL1:33,ORDINAL2:27; then succ A c= succ B & succ B in sup phi by A3,ORDINAL1:22,ORDINAL2:1; hence succ A in sup phi by ORDINAL1:22; end; hence thesis by ORDINAL1:41; end; Lm2: rng f c= X implies (g|X)*f = g*f proof assume rng f c= X; then f"rng f c= f"X & f"X c= dom f & f"rng f = dom f by RELAT_1:167,169,178; then A1: f"X = dom f & f"dom g c= dom f by RELAT_1:167,XBOOLE_0:def 10; A2: dom ((g|X)*f) = f"(dom (g|X)) by RELAT_1:182 .= f"(dom g /\ X) by RELAT_1:90 .= f"(dom g) /\ f"X by FUNCT_1:137 .= f"(dom g) by A1,XBOOLE_1:28 .= dom (g*f) by RELAT_1:182; (g|X)*f c= g*f by GRFUNC_1:54; hence thesis by A2,GRFUNC_1:9; end; theorem fi is increasing & fi is continuous & psi is continuous & phi = psi*fi implies phi is continuous proof assume that A1: fi is increasing and A2: for A,B st A in dom fi & A <> {} & A is_limit_ordinal & B = fi.A holds B is_limes_of fi|A and A3: for A,B st A in dom psi & A <> {} & A is_limit_ordinal & B = psi.A holds B is_limes_of psi|A and A4: phi = psi*fi; let A,B such that A5: A in dom phi & A <> {} & A is_limit_ordinal & B = phi.A; A6: dom phi c= dom fi & rng phi c= rng psi by A4,RELAT_1:44,45; reconsider A1 = fi.A as Ordinal; A7: rng (fi|A) c= sup rng (fi|A) proof let x; assume A8: x in rng (fi|A); then consider y such that A9: y in dom (fi|A) & x = (fi|A).y by FUNCT_1:def 5; reconsider y as Ordinal by A9,ORDINAL1:23; reconsider B = (fi|A).y as Ordinal; B in sup rng (fi|A) by A8,A9,ORDINAL2:27; hence thesis by A9; end; A c= dom fi by A5,A6,ORDINAL1:def 2; then A10: A1 is_limes_of fi|A & B = psi.A1 & A1 in dom psi & phi|A = psi*(fi|A ) & dom (fi|A) = A & A c= A1 & {} in A by A1,A2,A4,A5,A6,Th10,FUNCT_1:21,22,ORDINAL3:10,RELAT_1:91,112; then A11: fi|A is increasing & A1 c= dom psi & lim (fi|A) = A1 & {} in A1 by A1,Th15,ORDINAL1:def 2,ORDINAL2:def 14; then A12: dom (psi|A1) = A1 & sup (fi|A) = A1 & sup rng (fi|A) = sup (fi|A) & sup (fi|A) is_limit_ordinal & A1 <> {} by A5,A10,Th8,Th16,ORDINAL2:35,RELAT_1:91; then B is_limes_of psi|A1 & phi|A = (psi|A1)*(fi|A) by A3,A7,A10,Lm2; hence B is_limes_of phi|A by A11,A12,Th14; end; theorem (for A st A in dom fi holds fi.A = C+^A) implies fi is increasing proof assume A1: for A st A in dom fi holds fi.A = C+^A; let A,B; assume A2: A in B & B in dom fi; then A in dom fi by ORDINAL1:19; then fi.A = C+^A & fi.B = C+^B by A1,A2; hence thesis by A2,ORDINAL2:49; end; theorem Th19: C <> {} & (for A st A in dom fi holds fi.A = A*^C) implies fi is increasing proof assume that A1: C <> {} and A2: for A st A in dom fi holds fi.A = A*^C; let A,B; assume A3: A in B & B in dom fi; then A in dom fi by ORDINAL1:19; then fi.A = A*^C & fi.B = B*^C by A2,A3; hence thesis by A1,A3,ORDINAL2:57; end; theorem Th20: A <> {} implies exp({},A) = {} proof defpred FF[Ordinal] means $1 <> {} implies exp({},$1) = {}; A1: FF[{}]; A2: FF[B] implies FF[succ B] proof assume FF[B] & succ B <> {}; thus exp({},succ B) = {}*^exp({},B) by ORDINAL2:61 .= {} by ORDINAL2:52; end; A3: for B st B <> {} & B is_limit_ordinal & for C st C in B holds FF[C] holds FF[B] proof let A such that A4: A <> {} & A is_limit_ordinal and A5: for C st C in A holds FF[C] and A <> {}; deffunc F(Ordinal) = exp({},$1); consider fi such that A6: dom fi = A & for B st B in A holds fi.B = F(B) from OS_Lambda; {} is_limes_of fi proof per cases; case {} = {}; take B = one; {} in A by A4,ORDINAL3:10; hence B in dom fi by A4,A6,ORDINAL1:41,ORDINAL2:def 4; let D; assume A7: B c= D; assume D in dom fi; then FF[D] & fi.D = exp({},D) by A5,A6; hence fi.D = {} by A7,ORDINAL1:33,ORDINAL2:def 4; case {} <> {}; thus thesis; end; then lim fi = {} & exp({},A) = lim fi by A4,A6,ORDINAL2:62,def 14; hence thesis; end; FF[B] from Ordinal_Ind(A1,A2,A3); hence thesis; end; Lm3: A <> {} & A is_limit_ordinal implies for fi st dom fi = A & for B st B in A holds fi.B = exp({},B) holds {} is_limes_of fi proof assume A1: A <> {} & A is_limit_ordinal; let fi; assume A2: dom fi = A & for B st B in A holds fi.B = exp({},B); per cases; case {} = {}; take B = one; {} in A by A1,ORDINAL3:10; hence B in dom fi by A1,A2,ORDINAL1:41,ORDINAL2:def 4; let D; assume B c= D & D in dom fi; then D <> {} & exp({},D) = fi.D by A2,ORDINAL1:33,ORDINAL2:def 4 ; hence fi.D = {} by Th20; case {} <> {}; thus thesis; end; Lm4: A <> {} & A is_limit_ordinal implies for fi st dom fi = A & for B st B in A holds fi.B = exp(one,B) holds one is_limes_of fi proof assume A1: A <> {} & A is_limit_ordinal; let fi; assume A2: dom fi = A & for B st B in A holds fi.B = exp(one,B); per cases; case one = {}; hence thesis; case one <> {}; let A1,A2 be Ordinal such that A3: A1 in one & one in A2; take B = {}; thus B in dom fi by A1,A2,ORDINAL3:10; let D; assume B c= D & D in dom fi; then exp(one,D) = fi.D & exp(one,D) = one by A2,ORDINAL2:63; hence thesis by A3; end; Lm5: for A st A <> {} & A is_limit_ordinal holds ex fi st dom fi = A & (for B st B in A holds fi.B = exp(C,B)) & ex D st D is_limes_of fi proof defpred P[Ordinal] means $1 <> {} & $1 is_limit_ordinal & for fi st dom fi = $1 & for B st B in $1 holds fi.B = exp(C,B) for D holds not D is_limes_of fi; let A such that A1: A <> {} & A is_limit_ordinal & for fi st dom fi = A & for B st B in A holds fi.B = exp(C,B) for D holds not D is_limes_of fi; A2: ex A st P[A] by A1; consider A such that A3:P[A] and A4:for A1 st P[A1] holds A c= A1 from Ordinal_Min(A2); deffunc F(Ordinal) = exp(C,$1); consider fi such that A5: dom fi = A & for B st B in A holds fi.B = F(B) from OS_Lambda; A6: now assume C = {} or C = one; then {} is_limes_of fi or one is_limes_of fi by A3,A5,Lm3,Lm4; hence contradiction by A3,A5; end; then {} in C by ORDINAL3:10; then one c= C by ORDINAL1:33,ORDINAL2:def 4; then one c< C by A6,XBOOLE_0:def 8; then A7: one in C by ORDINAL1:21; A8: for B2,B1 being Ordinal st B1 in B2 & B2 in A holds exp(C,B1) in exp(C,B2) proof defpred V[Ordinal] means for B1 being Ordinal st B1 in $1 & $1 in A holds exp(C,B1) in exp(C,$1); A9: V[{}]; A10: V[B] implies V[succ B] proof assume A11: for B1 being Ordinal st B1 in B & B in A holds exp(C,B1) in exp(C,B); let B1 be Ordinal such that A12: B1 in succ B & succ B in A; A13: exp(C,B) <> {} proof now per cases; suppose B = {}; hence thesis by ORDINAL2:60; suppose B <> {}; then A14: {} in B by ORDINAL3:10; B in succ B by ORDINAL1:10; then B in A by A12,ORDINAL1:19; hence thesis by A11,A14; end; hence thesis; end; A15: exp(C,succ B) = C*^exp(C,B) & one*^exp(C,B) = exp(C,B) & B in succ B by ORDINAL1:10,ORDINAL2:56,61; then A16: exp(C,B) in exp(C,succ B) & B in A & B1 c= B by A7,A12,A13,ORDINAL1:19,34,ORDINAL2:57; now assume B1 <> B; then B1 c< B by A16,XBOOLE_0:def 8; then B1 in B by ORDINAL1:21; then exp(C,B1) in exp(C,B) by A11,A16; hence thesis by A16,ORDINAL1:19; end; hence thesis by A7,A13,A15,ORDINAL2:57; end; A17: for B st B <> {} & B is_limit_ordinal & for D st D in B holds V[D] holds V[B] proof let B such that A18: B <> {} & B is_limit_ordinal and A19: for D st D in B holds V[D]; let B1 be Ordinal; assume A20: B1 in B & B in A; then not A c= B by ORDINAL1:7; then consider psi such that A21: dom psi = B & (for D st D in B holds psi.D = exp(C,D)) & ex D st D is_limes_of psi by A4,A18; A22: exp(C,B) = lim psi by A18,A21,ORDINAL2:62; psi is increasing proof let B1,B2 be Ordinal; assume A23: B1 in B2 & B2 in dom psi; then V[B2] & B2 in A & B1 in B by A19,A20,A21,ORDINAL1:19; then exp(C,B1) in exp(C,B2) & psi.B1 = exp(C,B1) & psi.B2 = exp(C, B2) by A21,A23; hence thesis; end; then A24: lim psi = sup psi by A18,A21,Th8; psi.B1 = exp(C,B1) by A20,A21; then exp(C,B1) in rng psi & sup psi = sup rng psi by A20,A21,FUNCT_1:def 5,ORDINAL2:35; hence thesis by A22,A24,ORDINAL2:27; end; thus for B holds V[B] from Ordinal_Ind(A9,A10,A17); end; fi is increasing proof let B1,B2 be Ordinal; assume A25: B1 in B2 & B2 in dom fi; then B1 in dom fi by ORDINAL1:19; then exp(C,B1) in exp(C,B2) & fi.B1 = exp(C,B1) & fi.B2 = exp(C,B2) by A5 ,A8,A25; hence thesis; end; then sup fi is_limes_of fi by A3,A5,Th8; hence contradiction by A3,A5; end; theorem Th21: A <> {} & A is_limit_ordinal implies for fi st dom fi = A & for B st B in A holds fi.B = exp(C,B) holds exp(C,A) is_limes_of fi proof assume A1: A <> {} & A is_limit_ordinal; let fi such that A2: dom fi = A & for B st B in A holds fi.B = exp(C,B); consider psi such that A3: dom psi = A & for B st B in A holds psi.B = exp(C,B) and A4: ex D st D is_limes_of psi by A1,Lm5; now let x; assume A5: x in A; then reconsider B = x as Ordinal by ORDINAL1:23; thus fi.x = exp(C,B) by A2,A5 .= psi.x by A3,A5; end; then fi = psi by A2,A3,FUNCT_1:9; then consider D such that A6: D is_limes_of fi by A4; D = lim fi by A6,ORDINAL2:def 14 .= exp(C,A) by A1,A2,ORDINAL2:62; hence thesis by A6; end; theorem Th22: C <> {} implies exp(C,A) <> {} proof defpred P[Ordinal] means exp(C,$1) <> {}; assume A1: C <> {}; A2: P[{}] by ORDINAL2:60; A3: for A st P[A] holds P[succ A] proof let A such that A4: exp(C,A) <> {}; exp(C,succ A) = C*^exp(C,A) by ORDINAL2:61; hence thesis by A1,A4,ORDINAL3:34; end; A5: for A st A <> {} & A is_limit_ordinal & for B st B in A holds P[B] holds P[A] proof let A such that A6: A <> {} & A is_limit_ordinal and A7: for B st B in A holds exp(C,B) <> {}; consider fi such that A8: dom fi = A & (for B st B in A holds fi.B = exp(C,B)) & ex D st D is_limes_of fi by A6,Lm5; A9: exp(C,A) = lim fi by A6,A8,ORDINAL2:62; consider D such that A10: D is_limes_of fi by A8; A11: lim fi = D by A10,ORDINAL2:def 14; assume exp(C,A) = {}; then consider B such that A12: B in dom fi & for D st B c= D & D in dom fi holds fi.D = {} by A9,A10,A11,ORDINAL2:def 13; fi.B = exp(C,B) & exp(C,B) <> {} & fi.B = {} by A7,A8,A12; hence contradiction; end; for A holds P[A] from Ordinal_Ind(A2,A3,A5); hence thesis; end; theorem Th23: one in C implies exp(C,A) in exp(C,succ A) proof assume A1: one in C; then exp(C,A) <> {} & one*^exp(C,A) = exp(C,A) by Th22,ORDINAL2:56; then exp(C,succ A) = C*^exp(C,A) & exp(C,A) in C*^exp(C,A) by A1,ORDINAL2:57,61; hence thesis; end; theorem Th24: one in C & A in B implies exp(C,A) in exp(C,B) proof assume A1: one in C; defpred OO[Ordinal] means for A st A in $1 holds exp(C,A) in exp(C,$1); A2: OO[{}]; A3: for B st OO[B] holds OO[succ B] proof let B such that A4: for A st A in B holds exp(C,A) in exp(C,B); let A; assume A in succ B; then A5: A c= B by ORDINAL1:34; A6: exp(C,B) in exp(C,succ B) by A1,Th23; now assume A <> B; then A c< B by A5,XBOOLE_0:def 8; then A in B by ORDINAL1:21; hence exp(C,A) in exp(C,B) by A4; end; hence thesis by A6,ORDINAL1:19; end; A7: for B st B <> {} & B is_limit_ordinal & for D st D in B holds OO[D] holds OO[B] proof let B such that A8: B <> {} & B is_limit_ordinal and A9: for D st D in B holds OO[D]; let A such that A10: A in B; deffunc F(Ordinal) = exp(C,$1); consider fi such that A11: dom fi = B & (for D st D in B holds fi.D = F(D)) from OS_Lambda; A12: exp(C,B) = lim fi by A8,A11,ORDINAL2:62; fi is increasing proof let B1,B2 be Ordinal; assume A13: B1 in B2 & B2 in dom fi; then B1 in dom fi & OO[B2] by A9,A11,ORDINAL1:19; then fi.B1 = exp(C,B1) & fi.B2 = exp(C,B2) & exp(C,B1) in exp(C,B2) by A11,A13; hence thesis; end; then A14: sup fi = lim fi by A8,A11,Th8; fi.A = exp(C,A) by A10,A11; then exp(C,A) in rng fi & sup fi = sup rng fi by A10,A11,FUNCT_1:def 5, ORDINAL2:35; hence thesis by A12,A14,ORDINAL2:27; end; for B holds OO[B] from Ordinal_Ind(A2,A3,A7); hence thesis; end; theorem Th25: one in C & (for A st A in dom fi holds fi.A = exp(C,A)) implies fi is increasing proof assume A1: one in C & (for A st A in dom fi holds fi.A = exp(C,A)); let A,B; assume A2: A in B & B in dom fi; then A in dom fi by ORDINAL1:19; then fi.A = exp(C,A) & fi.B = exp(C,B) by A1,A2; hence fi.A in fi.B by A1,A2,Th24; end; theorem one in C & A <> {} & A is_limit_ordinal implies for fi st dom fi = A & for B st B in A holds fi.B = exp(C,B) holds exp(C,A) = sup fi proof assume A1: one in C & A <> {} & A is_limit_ordinal; let fi; assume A2: dom fi = A & for B st B in A holds fi.B = exp(C,B); then fi is increasing by A1,Th25; then lim fi = sup fi by A1,A2,Th8; hence thesis by A1,A2,ORDINAL2:62; end; theorem C <> {} & A c= B implies exp(C,A) c= exp(C,B) proof assume C <> {}; then {} in C by ORDINAL3:10; then A1: one c= C by ORDINAL1:33,ORDINAL2:def 4; A2: A c< B iff A c= B & A <> B by XBOOLE_0:def 8; assume A c= B; then A3: A in B or A = B by A2,ORDINAL1:21; now per cases; suppose C = one; then exp(C,A) = one & exp(C,B) = one by ORDINAL2:63; hence thesis; suppose C <> one; then one c< C by A1,XBOOLE_0:def 8; then one in C by ORDINAL1:21; then exp(C,A) in exp(C,B) or exp(C,A) = exp(C,B) by A3,Th24; hence thesis by ORDINAL1:def 2; end; hence thesis; end; theorem A c= B implies exp(A,C) c= exp(B,C) proof assume A1: A c= B; defpred P[Ordinal] means exp(A,$1) c= exp(B,$1); exp(A,{}) = one & exp(B,{}) = one by ORDINAL2:60; then A2: P[{}]; A3: for C st P[C] holds P[succ C] proof let C; exp(A,succ C) = A*^exp(A,C) & exp(B,succ C) = B*^exp(B,C) by ORDINAL2:61; hence thesis by A1,ORDINAL3:23; end; A4: for C st C <> {} & C is_limit_ordinal & for D st D in C holds P[D] holds P[C] proof let C; assume that A5: C <> {} & C is_limit_ordinal and A6: for D st D in C holds exp(A,D) c= exp(B,D); deffunc F(Ordinal) = exp(A,$1); consider f1 such that A7: dom f1 = C & for D st D in C holds f1.D = F(D) from OS_Lambda; deffunc F(Ordinal) = exp(B,$1); consider f2 such that A8: dom f2 = C & for D st D in C holds f2.D = F(D) from OS_Lambda; A9: exp(A,C) is_limes_of f1 & exp(B,C) is_limes_of f2 by A5,A7,A8,Th21; now let D; assume D in dom f1; then f1.D = exp(A,D) & f2.D = exp(B,D) & exp(A,D) c= exp(B,D) by A6,A7 ,A8; hence f1.D c= f2.D; end; hence exp(A,C) c= exp(B,C) by A7,A8,A9,Th6; end; for C holds P[C] from Ordinal_Ind(A2,A3,A4); hence thesis; end; theorem one in C & A <> {} implies one in exp(C,A) proof assume A1: one in C & A <> {}; then {} in A & exp(C,{}) = one by ORDINAL2:60,ORDINAL3:10; hence thesis by A1,Th24; end; theorem Th30: exp(C,A+^B) = exp(C,B)*^exp(C,A) proof defpred P[Ordinal] means exp(C,A+^$1) = exp(C,$1)*^exp(C,A); exp(C,A) = one*^exp(C,A) & one = exp(C,{}) by ORDINAL2:56,60; then A1: P[{}] by ORDINAL2:44; A2: for B st P[B] holds P[succ B] proof let B such that A3: exp(C,A+^B) = exp(C,B)*^exp(C,A); thus exp(C,A+^succ B) = exp(C,succ(A+^B)) by ORDINAL2:45 .= C*^exp(C,A+^B) by ORDINAL2:61 .= C*^exp(C,B)*^exp(C,A) by A3,ORDINAL3:58 .= exp(C,succ B)*^exp(C,A) by ORDINAL2:61; end; A4: for B st B <> {} & B is_limit_ordinal & for D st D in B holds P[D] holds P[B] proof let B such that A5: B <> {} & B is_limit_ordinal and A6: for D st D in B holds exp(C,A+^D) = exp(C,D)*^exp(C,A); deffunc F(Ordinal) = exp(C,$1); consider fi such that A7: dom fi = B & for D st D in B holds fi.D = F(D) from OS_Lambda; consider psi such that A8: dom psi = A+^B & for D st D in A+^B holds psi.D = F(D) from OS_Lambda; A+^B <> {} & A+^B is_limit_ordinal by A5,ORDINAL3:29,32; then A9: lim psi = exp(C,A+^B) by A8,ORDINAL2:62; deffunc F(Ordinal) = exp(C,$1); consider f1 such that A10: dom f1 = A & for D st D in A holds f1.D = F(D) from OS_Lambda; A11: dom psi = (dom f1)+^(dom(fi*^exp(C,A))) by A7,A8,A10,ORDINAL3:def 5; A12: now let D such that A13: D in dom f1; A c= A+^B by ORDINAL3:27; hence psi.D = exp(C,D) by A8,A10,A13 .= f1.D by A10,A13; end; A14: exp(C,B) is_limes_of fi by A5,A7,Th21; now let D; assume D in dom(fi*^exp(C,A)); then A15: D in dom fi by ORDINAL3:def 5; then A+^D in A+^B by A7,ORDINAL2:49; hence psi.((dom f1)+^D) = exp(C,A+^D) by A8,A10 .= (exp(C,D))*^exp(C,A) by A6,A7,A15 .= (fi.D)*^exp(C,A) by A7,A15 .= (fi*^exp(C,A)).D by A15,ORDINAL3:def 5; end; then psi = f1^(fi*^exp(C,A)) & exp(C,B)*^exp(C,A) is_limes_of fi*^exp(C ,A) by A11,A12,A14,Def1,Th5; then exp(C,B)*^exp(C,A) is_limes_of psi by Th3; hence thesis by A9,ORDINAL2:def 14; end; for B holds P[B] from Ordinal_Ind(A1,A2,A4); hence thesis; end; theorem exp(exp(C,A),B) = exp(C,B*^A) proof defpred P[Ordinal] means exp(exp(C,A),$1) = exp(C,$1*^A); exp(exp(C,A),{}) = one & exp(C,{}) = one by ORDINAL2:60; then A1: P[{}] by ORDINAL2:52; A2: for B st P[B] holds P[succ B] proof let B; assume exp(exp(C,A),B) = exp(C,B*^A); hence exp(exp(C,A),succ B) = exp(C,A)*^exp(C,B*^A) by ORDINAL2:61 .= exp(C,B*^A+^A) by Th30 .= exp(C,(succ B)*^A) by ORDINAL2:53; end; A3: for B st B <> {} & B is_limit_ordinal & for D st D in B holds P[D] holds P[B] proof let B; assume that A4: B <> {} & B is_limit_ordinal and A5: for D st D in B holds exp(exp(C,A),D) = exp(C,D*^A); deffunc F(Ordinal) = exp(exp(C,A),$1); consider fi such that A6: dom fi = B & for D st D in B holds fi.D = F(D) from OS_Lambda; deffunc F(Ordinal) = $1*^A; consider f1 such that A7: dom f1 = B & for D st D in B holds f1.D = F(D) from OS_Lambda; deffunc F(Ordinal) = exp(C,$1); consider f2 such that A8: dom f2 = B*^A & for D st D in B*^A holds f2.D = F(D) from OS_Lambda; A9: exp(C,{}) = one & B*^{} = {} by ORDINAL2:55,60; now assume A10: A <> {}; A11: dom(f2*f1) = B proof thus dom(f2*f1) c= B by A7,RELAT_1:44; let x; assume A12: x in B; then reconsider E = x as Ordinal by ORDINAL1:23; E*^A in B*^A & f1.E = E*^A by A7,A10,A12,ORDINAL2:57; hence thesis by A7,A8,A12,FUNCT_1:21; end; now let x; assume A13: x in B; then reconsider D = x as Ordinal by ORDINAL1:23; A14: D*^A in B*^A & f1.D = D*^A by A7,A10,A13,ORDINAL2:57; thus fi.x = exp(exp(C,A),D) by A6,A13 .= exp(C,D*^A) by A5,A13 .= f2.(f1.D) by A8,A14 .= (f2*f1).x by A7,A13,FUNCT_1:23; end; then A15: fi = f2*f1 by A6,A11,FUNCT_1:9; B*^A <> {} & B*^A is_limit_ordinal by A4,A10,ORDINAL3:34,48; then A16: exp(C,B*^A) is_limes_of f2 by A8,Th21; A17: rng f1 c= dom f2 proof let x; assume x in rng f1; then consider y such that A18: y in dom f1 & x = f1.y by FUNCT_1:def 5; reconsider y as Ordinal by A18,ORDINAL1:23; x = y*^A & y*^A in B*^A by A7,A10,A18,ORDINAL2:57; hence thesis by A8; end; A19: sup rng f1 = dom f2 proof sup rng f1 c= sup dom f2 by A17,ORDINAL2:30; hence sup rng f1 c= dom f2 by ORDINAL2:26; let x; assume A20: x in dom f2; then reconsider D = x as Ordinal by ORDINAL1:23; consider A1 such that A21: A1 in B & D in A1*^A by A4,A8,A20,ORDINAL3:49; f1.A1 = A1*^A by A7,A21; then A1*^A in rng f1 by A7,A21,FUNCT_1:def 5; then A1*^A in sup rng f1 by ORDINAL2:27; hence thesis by A21,ORDINAL1:19; end; f1 is increasing by A7,A10,Th19; then exp(C,B*^A) is_limes_of fi by A15,A16,A19,Th14; then exp(C,B*^A) = lim fi by ORDINAL2:def 14; hence thesis by A4,A6,ORDINAL2:62; end; hence exp(exp(C,A),B) = exp(C,B*^A) by A9,ORDINAL2:63; end; for B holds P[B] from Ordinal_Ind(A1,A2,A3); hence thesis; end; theorem one in C implies A c= exp(C,A) proof assume A1: one in C; defpred P[Ordinal] means $1 c= exp(C,$1); A2: P[{}] by XBOOLE_1:2; A3: P[B] implies P[succ B] proof assume A4: B c= exp(C,B); exp(C,B) <> {} & exp(C,succ B) = C*^exp(C,B) & exp(C,B) = one*^exp(C,B) by A1,Th22,ORDINAL2:56,61; then exp(C,B) in exp(C,succ B) by A1,ORDINAL2:57; then B in exp(C,succ B) by A4,ORDINAL1:22; hence thesis by ORDINAL1:33; end; A5: for A st A <> {} & A is_limit_ordinal & for B st B in A holds P[B] holds P[A] proof let A such that A6: A <> {} & A is_limit_ordinal and A7: for B st B in A holds B c= exp(C,B); deffunc F(Ordinal) = exp(C,$1); consider fi such that A8: dom fi = A & for B st B in A holds fi.B = F(B) from OS_Lambda; fi is increasing by A1,A8,Th25; then A9: sup fi = lim fi by A6,A8,Th8 .= exp(C,A) by A6,A8,ORDINAL2:62; let x; assume A10: x in A; then reconsider B = x as Ordinal by ORDINAL1:23; fi.B = exp(C,B) by A8,A10; then exp(C,B) in rng fi & sup fi = sup rng fi by A8,A10,FUNCT_1:def 5,ORDINAL2:35; then B c= exp(C,B) & exp(C,B) in sup fi by A7,A10,ORDINAL2:27; hence x in exp(C,A) by A9,ORDINAL1:22; end; P[B] from Ordinal_Ind(A2,A3,A5); hence thesis; end; scheme CriticalNumber { phi(Ordinal) -> Ordinal } : ex A st phi(A) = A provided A1: for A,B st A in B holds phi(A) in phi(B) and A2: for A st A <> {} & A is_limit_ordinal for phi st dom fi = A & for B st B in A holds phi.B = phi(B) holds phi(A) is_limes_of phi proof assume A3: not thesis; deffunc F(Ordinal,Ordinal) = phi($2); deffunc G(Ordinal,T-Sequence) = {}; consider phi such that A4: dom phi = omega and A5: {} in omega implies phi.{} = phi({}) and A6: for A st succ A in omega holds phi.(succ A) = F(A,phi.A) and for A st A in omega & A <> {} & A is_limit_ordinal holds phi.A = G(A,phi|A) from OS_Exist; A7: now defpred P[Ordinal] means not $1 c= phi($1); assume A8: ex A st P[A]; consider A such that A9: P[A] and A10: for B st P[B] holds A c= B from Ordinal_Min(A8); phi(A) in A by A9,ORDINAL1:26; then phi(phi(A)) in phi(A) by A1; then not phi(A) c= phi(phi(A)) by ORDINAL1:7; hence contradiction by A9,A10; end; A11: now let A; A c= phi(A) & A <> phi(A) by A3,A7; then A c< phi(A) by XBOOLE_0:def 8; hence A in phi(A) by ORDINAL1:21; end; A12: phi is increasing proof let A,B; assume A13: A in B & B in dom phi; then A14: ex C st B = A+^C & C <> {} by ORDINAL3:31; defpred R[Ordinal] means A+^$1 in omega & $1 <> {} implies phi.A in phi.(A+^$1); A15: R[{}]; A16: for C st R[C] holds R[succ C] proof let C such that A17: A+^C in omega & C <> {} implies phi.A in phi.(A+^C) and A18: A+^succ C in omega & succ C <> {}; A19: A+^C in succ(A+^C) & A+^succ C = succ(A+^C) by ORDINAL1:10,ORDINAL2:45; reconsider D = phi.(A+^C) as Ordinal; phi.(A+^succ C) = phi(D) & D in phi(D) & A+^{} = A by A6,A11,A18,A19,ORDINAL2:44; hence thesis by A17,A18,A19,ORDINAL1:19; end; A20: for B st B <> {} & B is_limit_ordinal & for C st C in B holds R[C] holds R[B] proof let B such that A21: B <> {} & B is_limit_ordinal and for C st C in B holds A+^C in omega & C <> {} implies phi.A in phi.(A+^C) and A22: A+^B in omega & B <> {}; A+^B <> {} by A22,ORDINAL3:29; then A+^B is_limit_ordinal & {} in A+^B by A21,ORDINAL3:10,32; then omega c= A+^B by ORDINAL2:def 5; hence thesis by A22,ORDINAL1:7; end; for C holds R[C] from Ordinal_Ind(A15,A16,A20); hence thesis by A4,A13,A14; end; deffunc F(Ordinal) = phi ($1); consider fi such that A23: dom fi = sup phi & for A st A in sup phi holds fi.A = F(A) from OS_Lambda; phi({}) in rng phi & sup rng phi = sup phi by A4,A5,FUNCT_1:def 5,ORDINAL2:19,35; then A24: sup phi <> {} & sup phi is_limit_ordinal by A4,A12,Th16,ORDINAL2:19,27; then A25: phi(sup phi) is_limes_of fi by A2,A23; fi is increasing proof let A,B; assume A26: A in B & B in dom fi; then A in dom fi by ORDINAL1:19; then fi.A = phi(A) & fi.B = phi(B) by A23,A26; hence thesis by A1,A26; end; then A27: sup fi = lim fi by A23,A24,Th8 .= phi(sup phi) by A25,ORDINAL2:def 14; sup fi c= sup phi proof let x; assume A28: x in sup fi; then reconsider A = x as Ordinal by ORDINAL1:23; A29: sup fi = sup rng fi & sup phi = sup rng phi by ORDINAL2:35; then consider B such that A30: B in rng fi & A c= B by A28,ORDINAL2:29; consider y such that A31: y in dom fi & B = fi.y by A30,FUNCT_1:def 5; reconsider y as Ordinal by A31,ORDINAL1:23; consider C such that A32: C in rng phi & y c= C by A23,A29,A31,ORDINAL2:29; consider z such that A33: z in dom phi & C = phi.z by A32,FUNCT_1:def 5; reconsider z as Ordinal by A33,ORDINAL1:23; succ z in omega by A4,A33,ORDINAL1:41,ORDINAL2:19; then A34: phi.succ z = phi(C) & phi.succ z in rng phi & B = phi(y) by A4,A6,A23,A31,A33,FUNCT_1:def 5; y c< C iff y <> C & y c= C by XBOOLE_0:def 8; then y in C or y = C by A32,ORDINAL1:21; then phi(y) in phi(C) or y = C by A1; then B c= phi(C) & phi(C) in sup phi by A29,A34,ORDINAL1:def 2,ORDINAL2:27; then B in sup phi by ORDINAL1:22; hence thesis by A30,ORDINAL1:22; end; then not sup phi in phi(sup phi) by A27,ORDINAL1:7; hence contradiction by A11; end; reserve W for Universe; definition let W; mode Ordinal of W -> Ordinal means: Def2: it in W; existence proof On W <> {} by CLASSES2:55; then {} in On W & On W c= W by ORDINAL2:9,ORDINAL3:10; hence thesis; end; mode Ordinal-Sequence of W -> Ordinal-Sequence means: Def3: dom it = On W & rng it c= On W; existence proof deffunc F(Ordinal) = {}; consider phi such that A1: dom phi = On W & for A st A in On W holds phi.A = F(A) from OS_Lambda; take phi; thus dom phi = On W by A1; let x; assume x in rng phi; then consider y such that A2: y in dom phi & x = phi.y by FUNCT_1:def 5; reconsider y as Ordinal by A2,ORDINAL1:23; phi.y = {} & On W <> {} by A1,A2; hence x in On W by A2,ORDINAL3:10; end; end; definition let W; cluster non empty Ordinal of W; existence proof On W <> {} by CLASSES2:55; then {} in On W & On W c= W by ORDINAL2:9,ORDINAL3:10; then one in W by CLASSES2:6,ORDINAL2:def 4; then one is non empty & one is Ordinal of W by Def2; hence thesis; end; end; reserve A1,B1 for Ordinal of W, phi for Ordinal-Sequence of W; scheme UOS_Lambda { W() -> Universe, F(set) -> Ordinal of W() } : ex phi being Ordinal-Sequence of W() st for a being Ordinal of W() holds phi.a = F(a) proof deffunc FF(Ordinal) = F($1); consider psi such that A1:dom psi = On W() & for A st A in On W() holds psi.A = FF(A) from OS_Lambda; rng psi c= On W() proof let x; assume x in rng psi; then consider y such that A2: y in dom psi & x = psi.y by FUNCT_1:def 5; reconsider y as Ordinal by A2,ORDINAL1:23; x = F(y) & F(y) in W() by A1,A2,Def2; hence thesis by ORDINAL2:def 2; end; then reconsider phi = psi as Ordinal-Sequence of W() by A1,Def3; take phi; let a be Ordinal of W(); a in W() by Def2; then a in On W() by ORDINAL2:def 2; hence thesis by A1; end; definition let W; func 0-element_of W -> Ordinal of W equals: Def4: {}; correctness proof On W <> {} by CLASSES2:55; then {} in On W & On W c= W by ORDINAL2:9,ORDINAL3:10; then reconsider A = {} as Ordinal of W by Def2; A = {}; hence thesis; end; func 1-element_of W -> non empty Ordinal of W equals: Def5: one; correctness proof On W <> {} by CLASSES2:55; then {} in On W & On W c= W by ORDINAL2:9,ORDINAL3:10; then one in W by CLASSES2:6,ORDINAL2:def 4; then reconsider A = one as Ordinal of W by Def2; A = one; hence thesis; end; let phi,A1; redefine func phi.A1 -> Ordinal of W; coherence proof A1 in W by Def2; then A1: A1 in On W & dom phi = On W by Def3,ORDINAL2:def 2; reconsider B = phi.A1 as Ordinal; B in rng phi & rng phi c= On W by A1,Def3,FUNCT_1:def 5; then B in On W & On W c= W by ORDINAL2:9; hence thesis by Def2; end; end; definition let W; let p2,p1 be Ordinal-Sequence of W; redefine func p1*p2 -> Ordinal-Sequence of W; coherence proof dom p1 = On W & dom p2 = On W & rng p2 c= On W by Def3; then A1: dom(p1*p2) = On W & rng(p1*p2) c= rng p1 & rng p1 c= On W by Def3,RELAT_1:45,46; then reconsider f = p1*p2 as T-Sequence by ORDINAL1:def 7; A2: rng f c= On W by A1,XBOOLE_1:1; then reconsider f as Ordinal-Sequence by ORDINAL2:def 8; f is Ordinal-Sequence of W by A1,A2,Def3; hence thesis; end; end; canceled 2; theorem 0-element_of W = {} & 1-element_of W = one by Def4,Def5; definition let W,A1; redefine func succ A1 -> non empty Ordinal of W; coherence proof A1 in W & W is_Tarski-Class by Def2; then succ A1 in W by CLASSES2:6; hence thesis by Def2; end; let B1; func A1 +^ B1 -> Ordinal of W; coherence proof defpred P[Ordinal] means $1 in W implies A1+^$1 in W; A1: for B st for C st C in B holds P[C] holds P[B] proof let B such that A2: for C st C in B holds C in W implies A1+^C in W and A3: B in W; 0-element_of W in W & 1-element_of W in W by Def2; then A4: {0-element_of W} in W & {1-element_of W} in W & A1 in W by Def2,CLASSES2:63; then [:A1,{0-element_of W}:] in W & [:B,{1-element_of W}:] in W by A3,CLASSES2:67; then [:A1,{0-element_of W}:] \/ [:B,{1-element_of W}:] in W & {} <> succ {} & W is_Tarski-Class & 0-element_of W = {} & 1-element_of W = one by Def4,Def5,CLASSES2:66; then A5: Card(A1+^B) = Card([:A1,{0-element_of W}:] \/ [:B,{1-element_of W}:] ) & Card([:A1,{0-element_of W}:] \/ [:B,{1-element_of W}:]) <` Card W by CARD_2:16,CLASSES2:1; A1+^B c= W proof let x; assume A6: x in A1+^B; then reconsider A = x as Ordinal by ORDINAL1:23; A7: A1 c= W & (A in A1 or A1 c= A) by A4,ORDINAL1:26,def 2; now assume A1 c= A; then consider C such that A8: A = A1+^C by ORDINAL3:30; C in B & B c= W by A3,A6,A8,ORDINAL1:def 2,ORDINAL3:25; hence x in W by A2,A8; end; hence thesis by A7; end; hence A1+^B in W by A5,CLASSES1:2; end; A9: for B holds P[B] from Transfinite_Ind(A1); B1 in W by Def2; then A1+^B1 in W by A9; hence thesis by Def2; end; end; definition let W,A1,B1; redefine func A1 *^ B1 -> Ordinal of W; coherence proof defpred P[Ordinal] means $1 in W implies $1*^B1 in W; A1: for A st for C st C in A holds P[C] holds P[A] proof let A such that A2: for C st C in A holds C in W implies C*^B1 in W and A3: A in W; A4: B1 in W & W is_Tarski-Class by Def2; then [:A,B1:] in W by A3,CLASSES2:67; then A5: Card(A*^B1) = Card [:A,B1:] & Card [:A,B1:] <` Card W by CARD_2:18,CLASSES2:1; A*^B1 c= W proof let x; assume A6: x in A*^B1; then reconsider B = x as Ordinal by ORDINAL1:23; B1 <> {} by A6,ORDINAL2:55; then consider C,D such that A7: B = C*^B1+^D & D in B1 by ORDINAL3:55; A8: B1 c= W & C*^B1 c= B by A4,A7,ORDINAL1:def 2,ORDINAL3:27; then C*^B1 in A*^B1 by A6,ORDINAL1:22; then C in A & A c= W by A3,ORDINAL1:def 2,ORDINAL3:37; then D in W & C*^B1 in W by A2,A7,A8; then reconsider CB = C*^B1, D as Ordinal of W by Def2; x = CB+^D by A7; hence thesis by Def2; end; hence A*^B1 in W by A5,CLASSES1:2; end; A9: for A holds P[A] from Transfinite_Ind(A1); A1 in W by Def2; then A1*^B1 in W by A9; hence thesis by Def2; end; end; theorem Th36: A1 in dom phi proof A1 in W & dom phi = On W by Def2,Def3; hence thesis by ORDINAL2:def 2; end; theorem Th37: dom fi in W & rng fi c= W implies sup fi in W proof assume A1: dom fi in W & rng fi c= W; rng fi = fi.:(dom fi) & W is_Tarski-Class by RELAT_1:146; then Card rng fi <=` Card dom fi & Card dom fi <` Card W by A1,CARD_2:3,CLASSES2:1; then Card rng fi <` Card W by ORDINAL1:22; then rng fi in W by A1,CLASSES1:2; then A2: union rng fi in W by CLASSES2:65; consider A such that A3: rng fi c= A by ORDINAL2:def 8; for x st x in rng fi holds x is Ordinal by A3,ORDINAL1:23; then reconsider B = union rng fi as Ordinal by ORDINAL1:35; A4: succ B in W by A2,CLASSES2:6; sup fi c= succ B proof let x; assume A5: x in sup fi; then reconsider A = x as Ordinal by ORDINAL1:23; sup fi = sup rng fi by ORDINAL2:35; then consider C such that A6: C in rng fi & A c= C by A5,ORDINAL2:29; C c= union rng fi by A6,ZFMISC_1:92; then A c= B by A6,XBOOLE_1:1; hence x in succ B by ORDINAL1:34; end; hence thesis by A4,CLASSES1:def 1; end; reserve L,L1 for T-Sequence; theorem phi is increasing & phi is continuous & omega in W implies ex A st A in dom phi & phi.A = A proof assume that A1: phi is increasing and A2: phi is continuous and A3: omega in W; assume A4: not thesis; reconsider N = phi.(0-element_of W) as Ordinal; deffunc C(Ordinal,Ordinal) = phi.$2; deffunc D(Ordinal,Ordinal) = {}; consider L such that A5: dom L = omega and A6: {} in omega implies L.{} = N and A7: for A st succ A in omega holds L.(succ A) = C(A,L.A) and for A st A in omega & A <> {} & A is_limit_ordinal holds L.A = D(A,L|A) from TS_Exist1; defpred P[Ordinal] means $1 in dom L implies L.$1 is Ordinal of W; A8: P[{}] by A5,A6; A9: for A st P[A] holds P[succ A] proof let A such that A10: A in dom L implies L.A is Ordinal of W and A11: succ A in dom L; A in succ A by ORDINAL1:10; then reconsider x = L.A as Ordinal of W by A10,A11,ORDINAL1:19; L.succ A = phi.x by A5,A7,A11; hence thesis; end; A12: for A st A <> {} & A is_limit_ordinal & for B st B in A holds P[B] holds P[A] proof let A such that A13: A <> {} & A is_limit_ordinal and for B st B in A holds B in dom L implies L.B is Ordinal of W and A14: A in dom L; {} in A by A13,ORDINAL3:10; then omega c= A by A13,ORDINAL2:def 5; hence thesis by A5,A14,ORDINAL1:7; end; A15: for A holds P[A] from Ordinal_Ind(A8,A9,A12); rng L c= sup rng L proof let x; assume A16: x in rng L; then consider y such that A17: y in dom L & x = L.y by FUNCT_1:def 5; reconsider y as Ordinal by A17,ORDINAL1:23; reconsider A = L.y as Ordinal of W by A15,A17; A in sup rng L by A16,A17,ORDINAL2:27; hence thesis by A17; end; then reconsider L as Ordinal-Sequence by ORDINAL2:def 8; A18: now let A1; A1 in dom phi by Th36; then A1 c= phi.A1 & A1 <> phi.A1 by A1,A4,Th10; then A1 c< phi.A1 by XBOOLE_0:def 8; hence A1 in phi.A1 by ORDINAL1:21; end; A19: L is increasing proof let A,B; assume A20: A in B & B in dom L; then A21: ex C st B = A+^C & C <> {} by ORDINAL3:31; defpred P[Ordinal] means A+^$1 in omega & $1 <> {} implies L.A in L.(A+^$1); A22: P[{}]; A23: for C st P[C] holds P[succ C] proof let C such that A24: A+^C in omega & C <> {} implies L.A in L.(A+^C) and A25: A+^succ C in omega & succ C <> {}; A26: A+^C in succ(A+^C) & A+^succ C = succ(A+^C) by ORDINAL1:10,ORDINAL2:45; then A+^C in omega & A in omega by A5,A20,A25,ORDINAL1:19; then reconsider D = L.(A+^C) as Ordinal of W by A5,A15; L.(A+^succ C) = phi.D & D in phi.D & A+^{} = A by A7,A18,A25,A26,ORDINAL2:44; hence thesis by A24,A25,A26,ORDINAL1:19; end; A27: for B st B <> {} & B is_limit_ordinal & for C st C in B holds P[C] holds P[B] proof let B such that A28: B <> {} & B is_limit_ordinal and for C st C in B holds A+^C in omega & C <> {} implies L.A in L.(A+^C) and A29: A+^B in omega & B <> {}; A+^B <> {} by A29,ORDINAL3:29; then A+^B is_limit_ordinal & {} in A+^B by A28,ORDINAL3:10,32; then omega c= A+^B by ORDINAL2:def 5; hence thesis by A29,ORDINAL1:7; end; for C holds P[C] from Ordinal_Ind(A22,A23,A27); hence thesis by A5,A20,A21; end; set fi = phi|sup L; N in rng L & sup rng L = sup L by A5,A6,FUNCT_1:def 5,ORDINAL2:19,35; then A30: sup L <> {} & sup L is_limit_ordinal by A5,A19,Th16,ORDINAL2:19,27; A31: rng L c= W proof let x; assume x in rng L; then consider y such that A32: y in dom L & x = L.y by FUNCT_1:def 5; reconsider y as Ordinal by A32,ORDINAL1:23; L.y is Ordinal of W by A15,A32; hence thesis by A32,Def2; end; then A33: sup L in W by A3,A5,Th37; then reconsider S = sup L as Ordinal of W by Def2; A34: S in On W & dom phi = On W by A33,Def3,ORDINAL2:def 2; then A35: phi.S is_limes_of fi by A2,A30,ORDINAL2:def 17; S c= dom phi by A34,ORDINAL1:def 2; then A36: dom fi = S by RELAT_1:91; fi is increasing proof let A,B; assume A37: A in B & B in dom fi; then A in dom fi & dom fi c= dom phi by FUNCT_1:76,ORDINAL1:19; then fi.A = phi.A & fi.B = phi.B & B in dom phi by A37,FUNCT_1:70; hence thesis by A1,A37,ORDINAL2:def 16; end; then A38: sup fi = lim fi by A30,A36,Th8 .= phi.(sup L) by A35,ORDINAL2:def 14 ; sup fi c= sup L proof let x; assume A39: x in sup fi; then reconsider A = x as Ordinal by ORDINAL1:23; A40: sup fi = sup rng fi & sup L = sup rng L by ORDINAL2:35; then consider B such that A41: B in rng fi & A c= B by A39,ORDINAL2:29; consider y such that A42: y in dom fi & B = fi.y by A41,FUNCT_1:def 5; reconsider y as Ordinal by A42,ORDINAL1:23; consider C such that A43: C in rng L & y c= C by A36,A40,A42,ORDINAL2:29; consider z such that A44: z in dom L & C = L.z by A43,FUNCT_1:def 5; reconsider z as Ordinal by A44,ORDINAL1:23; succ z in omega by A5,A44,ORDINAL1:41,ORDINAL2:19; then A45: L.succ z = phi.C & L.succ z in rng L & B = phi.y by A5,A7,A42,A44,FUNCT_1:70,def 5; reconsider C1 = C as Ordinal of W by A31,A43,Def2; y c< C1 iff y c= C1 & y <> C1 by XBOOLE_0:def 8; then y in C1 & C1 in dom phi or y = C by A31,A34,A43,ORDINAL1:21, ORDINAL2:def 2; then phi.y in phi.C1 or y = C1 by A1,ORDINAL2:def 16; then B c= phi.C1 & phi.C1 in sup L by A40,A45,ORDINAL1:def 2,ORDINAL2:27; then B in sup L by ORDINAL1:22; hence thesis by A41,ORDINAL1:22; end; then not S in phi.S by A38,ORDINAL1:7; hence contradiction by A18; end;