“…Recently, a number of planners based on the portfolio approach have been developed, and achieved impressive results in the last editions of the International Planning Competition (IPC6-8) [11,9,34]: they won, or got very close to winning, in almost every track in which they took part. Achieved results, and the aforementioned observations, let us presume that the future of AI planning will not only be focused on developing new planning algorithms, as in the last decades, but also on designing promising techniques for combining and exploiting them.…”