A Multivalued planning model for soft preconditions and preferences

In this work a model for planning with multivalued fluents and graded actions, that allows preferences specifications and plan metric, is introduced. This model is based on the infinity-valued Łukasiewicz logic. In multivalued planning, fluents can assume truth values in the interval [0, 1] and actions can be executed at different application degrees also varying in [0, 1]. The notions of planning problem and solution plan also reflect a multivalued approach. Multivalued fluents and graded actions allow to model many real situations where some features of the world are fuzzy and where actions can be executed with varying strength. Moreover, the specification of soft preconditions allows a more flexible model for the solution plan while the use of soft preferences increases the expressive power of the plan quality specification. A correct/complete algorithm which solves bounded multivalued planning problems based on MIP compilation is also described and a prototype implementation is presented.