  In Cabo and Groeneboom (1994) the remaining area of the left-lower convex
hull of a Poisson point process with intensity one in the first quadrant of the
plane was analyzed, using the methods of Groeneboom (1988), giving formulas for
the expectation and variance of the remaining area for a finite interval of
slopes of the boundary of the convex hull. However, the time inversion argument
of Groeneboom (1988) was not correctly applied in Cabo and Groeneboom (1994),
leading to an incorrect scaling constant for the variance. The purpose of this
note is to show how the correct application of the time inversion argument
gives the right expression, which is in accordance with results in Nagaev and
Khamdamov (1991) and Buchta (2003).
