let IT1, IT2 be RealMap of [:(TOP-REAL n),(TOP-REAL n):]; ( ( for p, q being Point of holds IT1 . p,q = |.(p - q).| ) & ( for p, q being Point of holds IT2 . p,q = |.(p - q).| ) implies IT1 = IT2 )
assume that
A4:
for p, q being Point of holds IT1 . p,q = |.(p - q).|
and
A5:
for p, q being Point of holds IT2 . p,q = |.(p - q).|
; IT1 = IT2
now let p,
q be
Point of ;
IT1 . p,q = IT2 . p,qthus IT1 . p,
q =
|.(p - q).|
by A4
.=
IT2 . p,
q
by A5
;
verum end;
hence
IT1 = IT2
by A1, BINOP_1:2; verum