|g|(z) = var(g, (-, z]) for z × L

Then mg can be extended to an additive measure mg : E on the ring generated by the rectangles (z, z']. If g : × L is real valued, we have mg 0 if g is incrementally in

creasing. If g has finite variation |g|, then mg has finite variation |mg| on and|mg| = m|g|.