let n be Ordinal; :: thesis: for T being connected TermOrder of n
for L being non trivial right_complementable almost_left_invertible associative commutative well-unital distributive Abelian add-associative right_zeroed doubleLoopStr
for P being Subset of (Polynom-Ring n,L)
for f, g, h, h1 being Polynomial of n,L st f - g = h & PolyRedRel P,T reduces h,h1 holds
ex f1, g1 being Polynomial of n,L st
( f1 - g1 = h1 & PolyRedRel P,T reduces f,f1 & PolyRedRel P,T reduces g,g1 )

let T be connected TermOrder of n; :: thesis: for L being non trivial right_complementable almost_left_invertible associative commutative well-unital distributive Abelian add-associative right_zeroed doubleLoopStr
for P being Subset of (Polynom-Ring n,L)
for f, g, h, h1 being Polynomial of n,L st f - g = h & PolyRedRel P,T reduces h,h1 holds
ex f1, g1 being Polynomial of n,L st
( f1 - g1 = h1 & PolyRedRel P,T reduces f,f1 & PolyRedRel P,T reduces g,g1 )

let L be non trivial right_complementable almost_left_invertible associative commutative well-unital distributive Abelian add-associative right_zeroed doubleLoopStr ; :: thesis: for P being Subset of (Polynom-Ring n,L)
for f, g, h, h1 being Polynomial of n,L st f - g = h & PolyRedRel P,T reduces h,h1 holds
ex f1, g1 being Polynomial of n,L st
( f1 - g1 = h1 & PolyRedRel P,T reduces f,f1 & PolyRedRel P,T reduces g,g1 )

let P be Subset of (Polynom-Ring n,L); :: thesis: for f, g, h, h1 being Polynomial of n,L st f - g = h & PolyRedRel P,T reduces h,h1 holds
ex f1, g1 being Polynomial of n,L st
( f1 - g1 = h1 & PolyRedRel P,T reduces f,f1 & PolyRedRel P,T reduces g,g1 )

let f, g, h, h1 be Polynomial of n,L; :: thesis: ( f - g = h & PolyRedRel P,T reduces h,h1 implies ex f1, g1 being Polynomial of n,L st
( f1 - g1 = h1 & PolyRedRel P,T reduces f,f1 & PolyRedRel P,T reduces g,g1 ) )

assume A1: ( f - g = h & PolyRedRel P,T reduces h,h1 ) ; :: thesis: ex f1, g1 being Polynomial of n,L st
( f1 - g1 = h1 & PolyRedRel P,T reduces f,f1 & PolyRedRel P,T reduces g,g1 )

defpred S1[ Nat] means for f, g, h being Polynomial of n,L st f - g = h holds
for h1 being Polynomial of n,L
for p being RedSequence of PolyRedRel P,T st p . 1 = h & p . (len p) = h1 & len p = $1 holds
ex f1, g1 being Polynomial of n,L st
( f1 - g1 = h1 & PolyRedRel P,T reduces f,f1 & PolyRedRel P,T reduces g,g1 );
A2: S1[1]
proof
let f, g, h be Polynomial of n,L; :: thesis: ( f - g = h implies for h1 being Polynomial of n,L
for p being RedSequence of PolyRedRel P,T st p . 1 = h & p . (len p) = h1 & len p = 1 holds
ex f1, g1 being Polynomial of n,L st
( f1 - g1 = h1 & PolyRedRel P,T reduces f,f1 & PolyRedRel P,T reduces g,g1 ) )

assume A3: f - g = h ; :: thesis: for h1 being Polynomial of n,L
for p being RedSequence of PolyRedRel P,T st p . 1 = h & p . (len p) = h1 & len p = 1 holds
ex f1, g1 being Polynomial of n,L st
( f1 - g1 = h1 & PolyRedRel P,T reduces f,f1 & PolyRedRel P,T reduces g,g1 )

let h1 be Polynomial of n,L; :: thesis: for p being RedSequence of PolyRedRel P,T st p . 1 = h & p . (len p) = h1 & len p = 1 holds
ex f1, g1 being Polynomial of n,L st
( f1 - g1 = h1 & PolyRedRel P,T reduces f,f1 & PolyRedRel P,T reduces g,g1 )

let p be RedSequence of PolyRedRel P,T; :: thesis: ( p . 1 = h & p . (len p) = h1 & len p = 1 implies ex f1, g1 being Polynomial of n,L st
( f1 - g1 = h1 & PolyRedRel P,T reduces f,f1 & PolyRedRel P,T reduces g,g1 ) )

assume A4: ( p . 1 = h & p . (len p) = h1 & len p = 1 ) ; :: thesis: ex f1, g1 being Polynomial of n,L st
( f1 - g1 = h1 & PolyRedRel P,T reduces f,f1 & PolyRedRel P,T reduces g,g1 )

take f ; :: thesis: ex g1 being Polynomial of n,L st
( f - g1 = h1 & PolyRedRel P,T reduces f,f & PolyRedRel P,T reduces g,g1 )

take g ; :: thesis: ( f - g = h1 & PolyRedRel P,T reduces f,f & PolyRedRel P,T reduces g,g )
thus ( f - g = h1 & PolyRedRel P,T reduces f,f & PolyRedRel P,T reduces g,g ) by A3, A4, REWRITE1:13; :: thesis: verum
end;
A5: now
let k be Nat; :: thesis: ( 1 <= k & S1[k] implies S1[k + 1] )
assume A6: 1 <= k ; :: thesis: ( S1[k] implies S1[k + 1] )
assume A7: S1[k] ; :: thesis: S1[k + 1]
thus S1[k + 1] :: thesis: verum
proof
let f, g, h be Polynomial of n,L; :: thesis: ( f - g = h implies for h1 being Polynomial of n,L
for p being RedSequence of PolyRedRel P,T st p . 1 = h & p . (len p) = h1 & len p = k + 1 holds
ex f1, g1 being Polynomial of n,L st
( f1 - g1 = h1 & PolyRedRel P,T reduces f,f1 & PolyRedRel P,T reduces g,g1 ) )

assume A8: f - g = h ; :: thesis: for h1 being Polynomial of n,L
for p being RedSequence of PolyRedRel P,T st p . 1 = h & p . (len p) = h1 & len p = k + 1 holds
ex f1, g1 being Polynomial of n,L st
( f1 - g1 = h1 & PolyRedRel P,T reduces f,f1 & PolyRedRel P,T reduces g,g1 )

let h1 be Polynomial of n,L; :: thesis: for p being RedSequence of PolyRedRel P,T st p . 1 = h & p . (len p) = h1 & len p = k + 1 holds
ex f1, g1 being Polynomial of n,L st
( f1 - g1 = h1 & PolyRedRel P,T reduces f,f1 & PolyRedRel P,T reduces g,g1 )

let r be RedSequence of PolyRedRel P,T; :: thesis: ( r . 1 = h & r . (len r) = h1 & len r = k + 1 implies ex f1, g1 being Polynomial of n,L st
( f1 - g1 = h1 & PolyRedRel P,T reduces f,f1 & PolyRedRel P,T reduces g,g1 ) )

assume A9: ( r . 1 = h & r . (len r) = h1 & len r = k + 1 ) ; :: thesis: ex f1, g1 being Polynomial of n,L st
( f1 - g1 = h1 & PolyRedRel P,T reduces f,f1 & PolyRedRel P,T reduces g,g1 )

then A10: dom r = Seg (k + 1) by FINSEQ_1:def 3;
set h2 = r . k;
1 <= k + 1 by NAT_1:11;
then A11: k + 1 in dom r by A10, FINSEQ_1:3;
k <= k + 1 by NAT_1:11;
then k in dom r by A6, A10, FINSEQ_1:3;
then A12: [(r . k),(r . (k + 1))] in PolyRedRel P,T by A11, REWRITE1:def 2;
then consider x, y being set such that
A13: ( x in NonZero (Polynom-Ring n,L) & y in the carrier of (Polynom-Ring n,L) & [(r . k),(r . (k + 1))] = [x,y] ) by ZFMISC_1:def 2;
A14: r . k = [x,y] `1 by A13, MCART_1:def 1
.= x by MCART_1:def 1 ;
then reconsider h2 = r . k as Polynomial of n,L by A13, POLYNOM1:def 27;
0_ n,L = 0. (Polynom-Ring n,L) by POLYNOM1:def 27;
then not r . k in {(0_ n,L)} by A13, A14, XBOOLE_0:def 5;
then r . k <> 0_ n,L by TARSKI:def 1;
then reconsider h2 = h2 as non-zero Polynomial of n,L by POLYNOM7:def 2;
set q = r | (Seg k);
reconsider q = r | (Seg k) as FinSequence by FINSEQ_1:19;
A15: dom r = Seg (k + 1) by A9, FINSEQ_1:def 3;
A16: k <= k + 1 by NAT_1:11;
then A17: len q = k by A9, FINSEQ_1:21;
A18: dom q = Seg k by A9, A16, FINSEQ_1:21;
now
let i be Element of NAT ; :: thesis: ( i in dom q & i + 1 in dom q implies [(q . i),(q . (i + 1))] in PolyRedRel P,T )
assume A19: ( i in dom q & i + 1 in dom q ) ; :: thesis: [(q . i),(q . (i + 1))] in PolyRedRel P,T
then A20: ( 1 <= i & i <= k & 1 <= i + 1 & i + 1 <= k ) by A18, FINSEQ_1:3;
then A21: ( i <= k + 1 & i + 1 <= k + 1 ) by A16, XXREAL_0:2;
then A22: i in dom r by A15, A20, FINSEQ_1:3;
i + 1 in dom r by A15, A20, A21, FINSEQ_1:3;
then A23: [(r . i),(r . (i + 1))] in PolyRedRel P,T by A22, REWRITE1:def 2;
r . i = q . i by A19, FUNCT_1:70;
hence [(q . i),(q . (i + 1))] in PolyRedRel P,T by A19, A23, FUNCT_1:70; :: thesis: verum
end;
then reconsider q = q as RedSequence of PolyRedRel P,T by A6, A17, REWRITE1:def 2;
1 in dom q by A6, A18, FINSEQ_1:3;
then A24: q . 1 = h by A9, FUNCT_1:70;
A25: k in dom q by A6, A18, FINSEQ_1:3;
q . (len q) = q . k by A9, A16, FINSEQ_1:21
.= h2 by A25, FUNCT_1:70 ;
then consider f2, g2 being Polynomial of n,L such that
A26: ( f2 - g2 = h2 & PolyRedRel P,T reduces f,f2 & PolyRedRel P,T reduces g,g2 ) by A7, A8, A17, A24;
h2 reduces_to h1,P,T by A9, A12, Def13;
then consider p being Polynomial of n,L such that
A27: ( p in P & h2 reduces_to h1,p,T ) by Def7;
consider b being bag of such that
A28: h2 reduces_to h1,p,b,T by A27, Def6;
consider s being bag of such that
A29: ( s + (HT p,T) = b & h1 = h2 - (((h2 . b) / (HC p,T)) * (s *' p)) ) by A28, Def5;
set f1 = f2 - (((f2 . b) / (HC p,T)) * (s *' p));
set g1 = g2 - (((g2 . b) / (HC p,T)) * (s *' p));
A30: ((f2 . b) / (HC p,T)) + (- ((g2 . b) / (HC p,T))) = ((f2 . b) * ((HC p,T) " )) + (- ((g2 . b) / (HC p,T))) by VECTSP_1:def 23
.= ((f2 . b) * ((HC p,T) " )) + (- ((g2 . b) * ((HC p,T) " ))) by VECTSP_1:def 23
.= ((f2 . b) * ((HC p,T) " )) + ((- (g2 . b)) * ((HC p,T) " )) by VECTSP_1:41
.= ((f2 . b) + (- (g2 . b))) * ((HC p,T) " ) by VECTSP_1:def 18
.= ((f2 . b) + ((- g2) . b)) * ((HC p,T) " ) by POLYNOM1:def 22
.= ((f2 + (- g2)) . b) * ((HC p,T) " ) by POLYNOM1:def 21
.= ((f2 - g2) . b) * ((HC p,T) " ) by POLYNOM1:def 23
.= ((f2 - g2) . b) / (HC p,T) by VECTSP_1:def 23 ;
A31: (f2 - (((f2 . b) / (HC p,T)) * (s *' p))) - (g2 - (((g2 . b) / (HC p,T)) * (s *' p))) = (f2 - (((f2 . b) / (HC p,T)) * (s *' p))) + (- (g2 - (((g2 . b) / (HC p,T)) * (s *' p)))) by POLYNOM1:def 23
.= (f2 + (- (((f2 . b) / (HC p,T)) * (s *' p)))) + (- (g2 - (((g2 . b) / (HC p,T)) * (s *' p)))) by POLYNOM1:def 23
.= (f2 + (- (((f2 . b) / (HC p,T)) * (s *' p)))) + (- (g2 + (- (((g2 . b) / (HC p,T)) * (s *' p))))) by POLYNOM1:def 23
.= (f2 + (- (((f2 . b) / (HC p,T)) * (s *' p)))) + ((- g2) + (- (- (((g2 . b) / (HC p,T)) * (s *' p))))) by Th1
.= ((f2 + (- (((f2 . b) / (HC p,T)) * (s *' p)))) + (- g2)) + (((g2 . b) / (HC p,T)) * (s *' p)) by POLYNOM1:80
.= ((- (((f2 . b) / (HC p,T)) * (s *' p))) + (f2 + (- g2))) + (((g2 . b) / (HC p,T)) * (s *' p)) by POLYNOM1:80
.= (f2 + (- g2)) + ((- (((f2 . b) / (HC p,T)) * (s *' p))) + (((g2 . b) / (HC p,T)) * (s *' p))) by POLYNOM1:80
.= (f2 - g2) + ((- (((f2 . b) / (HC p,T)) * (s *' p))) + (((g2 . b) / (HC p,T)) * (s *' p))) by POLYNOM1:def 23
.= (f2 - g2) + (((- ((f2 . b) / (HC p,T))) * (s *' p)) + (((g2 . b) / (HC p,T)) * (s *' p))) by Th9
.= (f2 - g2) + (- (- (((- ((f2 . b) / (HC p,T))) + ((g2 . b) / (HC p,T))) * (s *' p)))) by Th10
.= (f2 - g2) + (- ((- ((- ((f2 . b) / (HC p,T))) + ((g2 . b) / (HC p,T)))) * (s *' p))) by Th9
.= (f2 - g2) - ((- ((- ((f2 . b) / (HC p,T))) + ((g2 . b) / (HC p,T)))) * (s *' p)) by POLYNOM1:def 23
.= (f2 - g2) - (((- (- ((f2 . b) / (HC p,T)))) + (- ((g2 . b) / (HC p,T)))) * (s *' p)) by RLVECT_1:45
.= h1 by A26, A29, A30, RLVECT_1:30 ;
A32: now
per cases ( not b in Support f2 or b in Support f2 ) ;
case A33: not b in Support f2 ; :: thesis: PolyRedRel P,T reduces f,f2 - (((f2 . b) / (HC p,T)) * (s *' p))
b is Element of Bags n by POLYNOM1:def 14;
then f2 . b = 0. L by A33, POLYNOM1:def 9;
then f2 - (((f2 . b) / (HC p,T)) * (s *' p)) = f2 - (((0. L) * ((HC p,T) " )) * (s *' p)) by VECTSP_1:def 23
.= f2 - ((0. L) * (s *' p)) by BINOM:1
.= f2 - (0_ n,L) by Th8
.= f2 by Th4 ;
hence PolyRedRel P,T reduces f,f2 - (((f2 . b) / (HC p,T)) * (s *' p)) by A26; :: thesis: verum
end;
case A34: b in Support f2 ; :: thesis: PolyRedRel P,T reduces f,f2 - (((f2 . b) / (HC p,T)) * (s *' p))
then f2 <> 0_ n,L by POLYNOM7:1;
then reconsider f2 = f2 as non-zero Polynomial of n,L by POLYNOM7:def 2;
( f2 <> 0_ n,L & p <> 0_ n,L ) by A27, Lm18, POLYNOM7:def 2;
then f2 reduces_to f2 - (((f2 . b) / (HC p,T)) * (s *' p)),p,b,T by A29, A34, Def5;
then f2 reduces_to f2 - (((f2 . b) / (HC p,T)) * (s *' p)),p,T by Def6;
then f2 reduces_to f2 - (((f2 . b) / (HC p,T)) * (s *' p)),P,T by A27, Def7;
then [f2,(f2 - (((f2 . b) / (HC p,T)) * (s *' p)))] in PolyRedRel P,T by Def13;
then PolyRedRel P,T reduces f2,f2 - (((f2 . b) / (HC p,T)) * (s *' p)) by REWRITE1:16;
hence PolyRedRel P,T reduces f,f2 - (((f2 . b) / (HC p,T)) * (s *' p)) by A26, REWRITE1:17; :: thesis: verum
end;
end;
end;
now
per cases ( not b in Support g2 or b in Support g2 ) ;
case A35: not b in Support g2 ; :: thesis: PolyRedRel P,T reduces g,g2 - (((g2 . b) / (HC p,T)) * (s *' p))
b is Element of Bags n by POLYNOM1:def 14;
then g2 . b = 0. L by A35, POLYNOM1:def 9;
then g2 - (((g2 . b) / (HC p,T)) * (s *' p)) = g2 - (((0. L) * ((HC p,T) " )) * (s *' p)) by VECTSP_1:def 23
.= g2 - ((0. L) * (s *' p)) by BINOM:1
.= g2 - (0_ n,L) by Th8
.= g2 by Th4 ;
hence PolyRedRel P,T reduces g,g2 - (((g2 . b) / (HC p,T)) * (s *' p)) by A26; :: thesis: verum
end;
case A36: b in Support g2 ; :: thesis: PolyRedRel P,T reduces g,g2 - (((g2 . b) / (HC p,T)) * (s *' p))
then g2 <> 0_ n,L by POLYNOM7:1;
then reconsider g2 = g2 as non-zero Polynomial of n,L by POLYNOM7:def 2;
( g2 <> 0_ n,L & p <> 0_ n,L ) by A27, Lm18, POLYNOM7:def 2;
then g2 reduces_to g2 - (((g2 . b) / (HC p,T)) * (s *' p)),p,b,T by A29, A36, Def5;
then g2 reduces_to g2 - (((g2 . b) / (HC p,T)) * (s *' p)),p,T by Def6;
then g2 reduces_to g2 - (((g2 . b) / (HC p,T)) * (s *' p)),P,T by A27, Def7;
then [g2,(g2 - (((g2 . b) / (HC p,T)) * (s *' p)))] in PolyRedRel P,T by Def13;
then PolyRedRel P,T reduces g2,g2 - (((g2 . b) / (HC p,T)) * (s *' p)) by REWRITE1:16;
hence PolyRedRel P,T reduces g,g2 - (((g2 . b) / (HC p,T)) * (s *' p)) by A26, REWRITE1:17; :: thesis: verum
end;
end;
end;
hence ex f1, g1 being Polynomial of n,L st
( f1 - g1 = h1 & PolyRedRel P,T reduces f,f1 & PolyRedRel P,T reduces g,g1 ) by A31, A32; :: thesis: verum
end;
end;
A37: for k being Nat st 1 <= k holds
S1[k] from NAT_1:sch 8(A2, A5);
consider p being RedSequence of PolyRedRel P,T such that
A38: ( p . 1 = h & p . (len p) = h1 ) by A1, REWRITE1:def 3;
consider k being Nat such that
A39: len p = k ;
k > 0 by A39;
then 1 <= k by NAT_1:14;
hence ex f1, g1 being Polynomial of n,L st
( f1 - g1 = h1 & PolyRedRel P,T reduces f,f1 & PolyRedRel P,T reduces g,g1 ) by A1, A37, A38, A39; :: thesis: verum