It is shown that if a normed
division ring has a norm which is “multiplication monotone” in the sense that
N(x) < N(x′) and N(y) < N(y′) imply N(xy) ≦ N(x′y′), and if the norm is
“commutative” in the sense that N(⋯xy⋯) = N(⋯yx⋯) for all x and y, then the
topology of that ring is given by an absolute value. A consequence of this result is
that if the norm of a connected normed ring with unity is multiplication
monotone and commutative then the ring is embeddable in the system of
quaternions.