let C be Function of [:COMPLEX,COMPLEX:],COMPLEX; :: thesis: for G being Function of [:REAL,REAL:],REAL
for x1, y1 being FinSequence of COMPLEX
for x2, y2 being FinSequence of REAL st x1 = x2 & y1 = y2 & len x1 = len y2 & ( for i being Element of NAT st i in dom x1 holds
C . ((x1 . i),(y1 . i)) = G . ((x2 . i),(y2 . i)) ) holds
C .: (x1,y1) = G .: (x2,y2)
let G be Function of [:REAL,REAL:],REAL; :: thesis: for x1, y1 being FinSequence of COMPLEX
for x2, y2 being FinSequence of REAL st x1 = x2 & y1 = y2 & len x1 = len y2 & ( for i being Element of NAT st i in dom x1 holds
C . ((x1 . i),(y1 . i)) = G . ((x2 . i),(y2 . i)) ) holds
C .: (x1,y1) = G .: (x2,y2)
let x1, y1 be FinSequence of COMPLEX ; :: thesis: for x2, y2 being FinSequence of REAL st x1 = x2 & y1 = y2 & len x1 = len y2 & ( for i being Element of NAT st i in dom x1 holds
C . ((x1 . i),(y1 . i)) = G . ((x2 . i),(y2 . i)) ) holds
C .: (x1,y1) = G .: (x2,y2)
let x2, y2 be FinSequence of REAL ; :: thesis: ( x1 = x2 & y1 = y2 & len x1 = len y2 & ( for i being Element of NAT st i in dom x1 holds
C . ((x1 . i),(y1 . i)) = G . ((x2 . i),(y2 . i)) ) implies C .: (x1,y1) = G .: (x2,y2) )
assume that
A1: x1 = x2 and
A2: y1 = y2 and
A3: len x1 = len y2 and
A4: for i being Element of NAT st i in dom x1 holds
C . ((x1 . i),(y1 . i)) = G . ((x2 . i),(y2 . i)) ; :: thesis: C .: (x1,y1) = G .: (x2,y2)
A5: len (G .: (x2,y2)) = len x1 by A1, A3, FINSEQ_2:72;

A6: now

let i be Nat; :: thesis: ( 1 <= i & i <= len (C .: (x1,y1)) implies (C .: (x1,y1)) . i = (G .: (x2,y2)) . i )
assume that
A7: 1 <= i and
A8: i <= len (C .: (x1,y1)) ; :: thesis: (C .: (x1,y1)) . i = (G .: (x2,y2)) . i
A9: i <= len x1 by A2, A3, A8, FINSEQ_2:72;
then A10: i in dom x1 by A7, FINSEQ_3:25;
A11: i in dom (G .: (x2,y2)) by A5, A7, A9, FINSEQ_3:25;
i in dom (C .: (x1,y1)) by A7, A8, FINSEQ_3:25;
hence (C .: (x1,y1)) . i = C . ((x1 . i),(y1 . i)) by FUNCOP_1:22
.= G . ((x2 . i),(y2 . i)) by A4, A10
.= (G .: (x2,y2)) . i by A11, FUNCOP_1:22 ;
:: thesis: verum

end;

len (C .: (x1,y1)) = len x1 by A2, A3, FINSEQ_2:72;
hence C .: (x1,y1) = G .: (x2,y2) by A5, A6, FINSEQ_1:14; :: thesis: verum