In this paper, reasoning methods for the interval-based modal temporal logic LLP which employs the modal operators sometimes, always, next, and chop are described. A constraint deduction approach is proposed and compared with a sequent calculus which has been developed as the basic machinery for the deductive planning system PHI which uses LLP as underlying formalism.

A well-known result of Ladner says that the satissability problem for K45, KD45, and S5 is NP-complete. This result implicitly assumes that there are innnitely many primitive propositions in the language; it is easy to see that the satissability problem for these logics becomes linear time if there are only nitely many primitive propositions in the language. By way of contrast, we show that the...

The logic S4LP combines the modal logic S4 with the justification logic LP. This is the case both axiomatically and semantically, though of course the real story is in the details. We introduce a simple restriction on the behavior of constants in S4LP, a restriction that has no effect on the LP sublogic. With this assumed, some very powerful derived rules are established. Then these are used to...

We propose a formalism for reasoning about actions based on multi-modal logic which allows for expressing observations as first-class objects. We introduce a new modal operator, namely [o | α], which allows us to capture the notion of perceiving an observation given that an action has taken place. Formulae of the type [o | α]φ mean ‘after perceiving observation o, given α was performed, necessa...

In this paper we introduce Epistemic Strategy Logic (ESL), an extension of Strategy Logic with modal operators for individual knowledge. This enhanced framework allows us to represent explicitly and to reason about the knowledge agents have of their own and other agents’ strategies. We provide a semantics to ESL in terms of epistemic concurrent game models, and consider the corresponding model ...

ions are relations between propositions, in which one is more abstract or general than another, let a be making a spaghetti-marinara dinner, and b be making a spaghetti dinner. In every possible world it is the case that a D b, so an intention to do a necessarily implies an intention to do b, if they are treated as normal modal operators. Normal modal operators are never abstraction free, but a...

In [4], Majer and Pelǐs proposed a relevant logic for epistemic agents, providing a novel extension of the relevant logic R with a distinctive epistemic modality K, which is at the one and the same time factive (Kφ → φ is a theorem) and an existential normal modal operator (K(φ ∨ ψ) → (Kφ ∨ Kψ) is also a theorem). The intended interpretation is that Kφ holds (relative to a situation s) if there...

We present the design of a cross-modal tool for collaborative diagram editing. The tool was designed to address the challenge of supporting collaborators who access a shared interactive space through different sets of modalities. This was achieved by augmenting a visual diagram editor with auditory and haptic views to allow simultaneous visual and non-visual interaction.

This paper describes the approach followed in the design of a service robot for health care applications. Under the auspices of the NASA Technology Transfer Program, a partnership was established between JPL and RWI, a manufacturer of mobile robots, to design and evaluate a mobile robot for health care assistance to the elderly and the handicapped. The activities of the rst phase of the project...