let X be ComplexUnitarySpace; :: thesis: for x, y being Point of X holds
( x <> y iff dist x,y > 0 )

let x, y be Point of X; :: thesis: ( x <> y iff dist x,y > 0 )
thus ( x <> y implies dist x,y > 0 ) :: thesis: ( dist x,y > 0 implies x <> y )
proof
assume x <> y ; :: thesis: dist x,y > 0
then dist x,y <> 0 by Th55;
hence dist x,y > 0 by Th46; :: thesis: verum
end;
thus ( dist x,y > 0 implies x <> y ) by Th53; :: thesis: verum