let F1, F2 be Function of (TopSpaceMetr M),R^1; :: thesis: ( ( for y being Point of M holds F1 . y = dist (y,x) ) & ( for y being Point of M holds F2 . y = dist (y,x) ) implies F1 = F2 )
assume A4: for y being Point of M holds F1 . y = dist (y,x) ; :: thesis: ( ex y being Point of M st not F2 . y = dist (y,x) or F1 = F2 )
assume A5: for y being Point of M holds F2 . y = dist (y,x) ; :: thesis: F1 = F2
for y being object st y in the carrier of (TopSpaceMetr M) holds
F1 . y = F2 . y
proof
let y be object ; :: thesis: ( y in the carrier of (TopSpaceMetr M) implies F1 . y = F2 . y )
A6: TopSpaceMetr M = TopStruct(# the carrier of M,(Family_open_set M) #) by PCOMPS_1:def 5;
assume y in the carrier of (TopSpaceMetr M) ; :: thesis: F1 . y = F2 . y
then reconsider y = y as Point of M by A6;
F1 . y = dist (y,x) by A4
.= F2 . y by A5 ;
hence F1 . y = F2 . y ; :: thesis: verum
end;
hence F1 = F2 by FUNCT_2:12; :: thesis: verum