Before revision:  The new integral equation allows to explicitly find the free-boundary b  in some so far unsolved cases, as when the operating profit function is not multiplicatively separable and X is a three- dimensional Bessel process or a CEV process.
After revision:  The new integral equation allows to explicitly find the free-boundary b (\cdot) in some so far unsolved cases, as when the operating profit function is not multiplicatively separable and X is a three- dimensional Bessel process or a CEV process.