Publications on Modal Logic
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Alberto Artosi and Guido Governatori.
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Popper on Necessity and Natural Laws.
In Mario Alai and Gino Tarozzi, editors,
Karl Popper Philosopher of Science.
pages 107-118. Rubbettino Editore,
Soveria Mannelli, 2006.
Abstract: During his philosophical career Popper sought to
characterize natural laws alternately as strictly universal and as
`naturally' or `physically' necessary statements. In this paper we
argue that neither characterization does what Popper claimed and
sketch a reconstruction of his views that avoids some of their major
drawbacks.
 
- Jeff Blee, David Billington, Guido Governatori, and
Abdul Sattar.
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Levels
of modalities for BDI logic.
In 2008 IEEE/WIC/ACM International Conference on Web Intelligence and
Intelligent Agent Technology, pages 647-650. IEEE Press,
2008, Copyright ©
2008 IEEE.
Abstract: The use of rational agents for modelling real world
problems has both been heavily investigated and become well accepted, with
BDI Logic being a widely used architecture to represent and reason about
rational agency. However, in the real world, we often have to deal with
different levels of confidence in our beliefs, desires, and intentions. This
paper extends our previous framework that integrated qualitative levels into
BDI Logic. We describe an expanded set of axioms and properties of the
extended logic and also define a detailed non-normal Kripke type semantics.
 
- Guido Governatori.
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Labelled modal
tableaux.
In Carlos Areces, Patrick Blackburn, and Rob Goldblatt, editors, Advances
in Modal Logic, volume 7. College Publications, London, 2008.
Abstract: Labelled tableaux are extensions of semantic tableaux
with annotations (labels, indices) whose main function is to enrich the modal
object language with semantic elements. This paper consists of three parts.
In the first part we consider some options for labels: simple constant labels
vs labels with free variables, logic depended inference rules vs labels
manipulation based on a label algebra. In the second and third part we
concentrate on a particular labelled tableaux system called KEM using free
variable and a specialised label algebra. Specifically in the second part we
show how labelled tableaux (KEM) can account for different types of logics
(e.g., non-normal modal logics and conditional logics). In the third and
final part we investigate the relative complexity of labelled tableaux
systems and we show that the uses of KEM's label algebra can lead to speed up
on proofs.
 
- Guido Governatori, Ian Hodkinson and Yde Venema (eds).
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- Advances in Modal
Logic. Vol. 6. College Press, London, 2006.
 
- Guido Governatori and Antonino Rotolo.
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De re modal semantics.
Bulletin of Symbolic Logic, 9 no. 2 pp. 259-260, June 2003.
 
- Guido Governatori and Antonino Rotolo.
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On the axiomatization of Elgesem's logic of
ability and agency.
Bulletin of Symbolic Logic, 10 in print, 2004.
 
- Guido Governatori and Antonino Rotolo.
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On
the axiomatization of Elgesem's logic of agency.
In Mark Reynold and Heinrich Wansing, editors, Advances in Modal Logic
5, Manchester, 8-11 September 2004.
Abstract: In this paper we show that the Hilbert system
of agency and ability presented by Dag Elgesem is incomplete with
respect to the intended semantics. We argue that completeness result
may be easily regained. Finally, we shortly discuss some issues
related to the philosophical intuition behind his approach. This is
done by examining Elgesem's modal logic of agency and ability using
semantics with different flavours.
 
- Guido Governatori and Antonino Rotolo.
-
On the axiomatization of ElgesemÃs logic
of agency and ability.
Journal of Philosophical Logic 34, 4, pp. 403-431.
The original publication is
available at
www.springerlink.com.
Abstract:In this paper we show that the Hilbert system of agency
and ability presented by Dag Elgesem is incomplete with respect to the
intended semantics. We argue that completeness result may be easily regained.
Finally, we shortly discuss some issues related to the philosophical
intuition behind his approach. This is done by examining Elgesem's modal
logic of agency and ability using semantics with different flavours.
 
- Vineet Padmanabhan, Guido Governatori, and Subhasis
Thakur.
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Knowledge
assessment: A modal logic approach.
In The Duy Bui, Tuong Vinh Ho, and Quang-Thuy Ha, editors, 11th Pacific
Rim International Conference on Multi-Agents (PRIMA 2008),
Lecture Notes in Computer Science 5357, pages 315-322.
Springer, 2008, Copy
rigth © 2008 Springer.
Abstract: The possible worlds semantics is a fruitful
approach used in Artificial Intelligence (AI) for both modelling as
well as reasoning about knowledge in agent systems via modal logics.
In this work our main idea is not to model/reason about knowledge but to
provide a theoretical framework for knowledge assessment (KA) with the
help of Monatague-Scott (MS) semantics of modal logic. In KA questions
asked and answers collected are the central elements and
knowledge notions will be defined from these (i.e., possible states of
knowledge of subjects in a population with respect to a field of
information).
 
- Kaile Su, Abdul Sattar, Guido Governatori, and Qingliang
Chen.
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A computationally grounded logic of knowledge, belief and certainty.
In Proceedings of The Fourth International Joint Conference on Autonomous
Agents and Multi Agent Systems (AAMAS 2005) ACM Press, 2005,
pp. 149-156. Copyright
© 2005, ACM Press.
Abstract:This paper develops a logic of knowledge,
belief and certainty, which allows us to explicitly mention an
agent's knowledge, belief and certainty in multi-agent systems. A
computationally grounded model, called interpreted KBC systems, is
given for interpreting this logic. The relationship between
knowledge, belief and certainty is explored. In particular, certainty
entails belief; and to the agent what it is certain of appears to be
knowledge. To characterize all valid formulas in our logic, we
provide a sound and complete proof system. We show that the validity
problem for the interpreted KBC systems is PSPACE-complete. Our proof
approach is based on the well-known tableau method. To formalize
those agents that are able to introspect their own belief and
certainty, we identify a subclass of interpreted $KBC$ systems,
called introspective KBC systems. The validity problem for
introspective KBC systems turns out to be co-NP complete, and is no
harder than propositional logic. We also give a sound and complete
proof system with respect to the introspective KBC systems.
 
- Kaile Su, Abdul Sattar, Kewen Wang, Xiangyu Luo, Guido
Governatori, and Vineet Nair.
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The observation-based model for BDI-agents.
In Proceedings of AAAI 2005In print. AAAI Press,
2005. Copyright © 2005. AAAI Press, 2005, pp. 190-195. Copyright ©
2005, AAAI, American Association for Artificial Intelligence.
Abstract:We present a new computational model of
BDI-agents, called the observation-based BDI-model. The key point of
this BDI-model is to express agents' beliefs, desires and intentions
as a set of runs (computing paths), which is exactly a system in the
interpreted system model, a well-known agent model due to Halpern and
his colleagues. Our BDI-model is computationally grounded in that we
are able to associate the BDI-agent model with a computer program, and
formulas, involving agents' beliefs, desires (goals) and intentions,
can be understood as properties of program computations. We present a
sound and complete proof system with respect to our BDI-model and
explore how symbolic model checking techniques can be applied to model
checking BDI-agents. In order to make our BDI-model more flexible and
practically realistic, we generalize it so that agents can have
multiple sources of beliefs, goals and intentions.
 
- Kaile Su, Abdul Sattar, Kewen Wang, and Guido
Governatori.
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Computationally grounded model of
{BDI}-agents.
Proceedings of IJCAI'05, 30 July - 3 August 2005,
pp. 1581-1582. Copyright © 2005
IJCAI.
Abstract:We introduce a multimodal logic of belief, desire and
intention, called OBDI logic, where the changes and computation of agents'
beliefs, desires, and desires are based on agents' observations (i.e. local
states), and we propose a model checking techniques for the logic based on
interpreted systems.