let i be Element of NAT ; :: thesis: for G being Go-board st 1 <= i & i <= len G holds
(SgmX RealOrd ,(proj1 .: (Values G))) . i = (G * i,1) `1

let G be Go-board; :: thesis: ( 1 <= i & i <= len G implies (SgmX RealOrd ,(proj1 .: (Values G))) . i = (G * i,1) `1 )
assume A1: ( 1 <= i & i <= len G ) ; :: thesis: (SgmX RealOrd ,(proj1 .: (Values G))) . i = (G * i,1) `1
deffunc H1( Nat) -> Element of REAL = (G * $1,1) `1 ;
consider f being FinSequence of REAL such that
A2: len f = len G and
A3: for i being Nat st i in dom f holds
f . i = H1(i) from FINSEQ_2:sch 1();
A4: dom f = Seg (len G) by A2, FINSEQ_1:def 3;
0 <> width G by GOBOARD1:def 5;
then A5: 1 <= width G by NAT_1:14;
reconsider A = proj1 .: (Values G) as finite Subset of REAL ;
A6: rng f = A
proof
A7: Values G = { (G * m,n) where m, n is Element of NAT : [m,n] in Indices G } by GOBRD13:7;
thus rng f c= A :: according to XBOOLE_0:def 10 :: thesis: A c= rng f
proof
let x be set ; :: according to TARSKI:def 3 :: thesis: ( not x in rng f or x in A )
assume A8: x in rng f ; :: thesis: x in A
then reconsider x = x as Element of REAL ;
consider y being set such that
A9: y in dom f and
A10: x = f . y by A8, FUNCT_1:def 5;
reconsider y = y as Element of NAT by A9;
( 1 <= y & y <= len G ) by A2, A9, FINSEQ_3:27;
then [y,1] in Indices G by A5, MATRIX_1:37;
then A11: G * y,1 in Values G by A7;
y in Seg (len G) by A2, A9, FINSEQ_1:def 3;
then x = (G * y,1) `1 by A3, A10, A4
.= proj1 . (G * y,1) by PSCOMP_1:def 28 ;
hence x in A by A11, FUNCT_2:43; :: thesis: verum
end;
let x be set ; :: according to TARSKI:def 3 :: thesis: ( not x in A or x in rng f )
assume A12: x in A ; :: thesis: x in rng f
then reconsider x = x as Element of REAL ;
consider p being Element of (TOP-REAL 2) such that
A13: p in Values G and
A14: x = proj1 . p by A12, FUNCT_2:116;
consider m, n being Element of NAT such that
A15: p = G * m,n and
A16: [m,n] in Indices G by A7, A13;
A17: ( 1 <= n & n <= width G ) by A16, MATRIX_1:39;
A18: ( 1 <= m & m <= len G ) by A16, MATRIX_1:39;
then A19: m in Seg (len G) by FINSEQ_1:3;
A20: m in dom f by A2, A18, FINSEQ_3:27;
x = p `1 by A14, PSCOMP_1:def 28
.= (G * m,1) `1 by A15, A17, A18, GOBOARD5:3
.= f . m by A3, A19, A4 ;
hence x in rng f by A20, FUNCT_1:def 5; :: thesis: verum
end;
for n, m being natural number st n in dom f & m in dom f & n < m holds
( f /. n <> f /. m & [(f /. n),(f /. m)] in RealOrd )
proof
let n, m be natural number ; :: thesis: ( n in dom f & m in dom f & n < m implies ( f /. n <> f /. m & [(f /. n),(f /. m)] in RealOrd ) )
assume that
A21: n in dom f and
A22: m in dom f and
A23: n < m ; :: thesis: ( f /. n <> f /. m & [(f /. n),(f /. m)] in RealOrd )
reconsider n' = n, m' = m as Element of NAT by ORDINAL1:def 13;
A24: ( f . n = (G * n',1) `1 & f . m = (G * m',1) `1 ) by A3, A21, A22;
A25: ( 1 <= n & m <= len G ) by A2, A21, A22, FINSEQ_3:27;
then A26: f . n' < f . m' by A5, A23, A24, GOBOARD5:4;
A27: ( f /. n = f . n & f /. m = f . m ) by A21, A22, PARTFUN1:def 8;
hence f /. n <> f /. m by A5, A23, A24, A25, GOBOARD5:4; :: thesis: [(f /. n),(f /. m)] in RealOrd
thus [(f /. n),(f /. m)] in RealOrd by A26, A27; :: thesis: verum
end;
then A28: f = SgmX RealOrd ,(proj1 .: (Values G)) by A6, TRIANG_1:4;
i in dom G by A1, FINSEQ_3:27;
then i in Seg (len G) by FINSEQ_1:def 3;
hence (SgmX RealOrd ,(proj1 .: (Values G))) . i = (G * i,1) `1 by A3, A28, A4; :: thesis: verum