

![0_image_0.png](0_image_0.png)

best algorithm is again DPI.WORST.BRANCH. Figure 10 gives the elicited preferences and user effort for this algorithm.

## 5.3 Incomplete Temporal Fuzzy Csps

We also performed some experiments on fuzzy simple temporal problems [8]. These problems have constraints of the form a ≤ x − y ≤ b modelling allowed time intervals for durations and distances of events, and fuzzy preferences associated to each element of an interval. We have generated classes of such problems following the approach in [8], adapted to consider incompleteness. While the class of problems generated in [8] is tractable, the presence of incompleteness makes them intractable in general. Figure 11 shows that in this specialized domain it is also possible to find a necessarily optimal solution by asking about 10% of the missing preferences, for example via algorithm DPI.WORST.BRANCH.

![0_image_1.png](0_image_1.png) 

## 6 Future Work

In the problems considered in this papers, we have no information about the missing preferences. We are currently considering settings in which each missing preference is