Proceedings of the 17th International Workshop on Nonmonotonic Reasoning (NMR), 2018, 2018
Revision operation is the consistent expansion of a theory by a new belief-representing sentence.... more Revision operation is the consistent expansion of a theory by a new belief-representing sentence. We consider that in a paraconsistent setting this desideratum can be accomplished in at least three distinct ways: the output of a revision operation should be either non-trivial or non-contradictory (in general or relative to the new belief). In this paper those distinctions will be explored in the constructive level by showing how the remainder sets could be refined, capturing the key concepts of paraconsistency in a dynamical scenario. These are preliminaries results of a wider project on Paraconsistent Belief Change conduced by the authors.
The 1985 paper by Carlos Alchourrón (1931–1996), Peter Gärdenfors, and David Makinson (AGM), “On ... more The 1985 paper by Carlos Alchourrón (1931–1996), Peter Gärdenfors, and David Makinson (AGM), “On the Logic of Theory Change: Partial Meet Contraction and Revision Functions” was the starting-point of a large and rapidly growing literature that employs formal models in the investigation of changes in belief states and databases. In this review, the first twenty-five years of this development are summarized. The topics covered include equivalent characterizations of AGM operations, extended representations of the belief states, change operators not included in the original framework, iterated change, applications of the model, its connections with other formal frameworks, computatibility of AGM operations, and criticism of the model.
This work elaborates on the connection between partial meet contractions and kernel contractions ... more This work elaborates on the connection between partial meet contractions and kernel contractions in belief change theory. We present a way to define incision functions (used in kernel con- tractions) from selection functions (used in partial meet contractions) and vice versa. Then we make precise under which conditions there are exact correspondences between selection and incision functions so that the
In this paper we adapt the Fermé and Hansson model of Shielded Contraction as well as Hansson et ... more In this paper we adapt the Fermé and Hansson model of Shielded Contraction as well as Hansson et al. Credibilitylimited Revision for belief bases, to join two of the many variations of the AGM model, i.e. those in which knowledge is represented through belief bases instead of logic theories, and those in which the object of the epistemic change does not have priority over the existing information as is the case in the AGM model.
Logic Journal of The Igpl / Bulletin of The Igpl, 2000
In recent papers Krister Segerberg introduced Irrevocable Belief Revision, as closely related to ... more In recent papers Krister Segerberg introduced Irrevocable Belief Revision, as closely related to AGM revision . In this paper we present irrevocable belief revision in terms of an epistemic entrenchment relation. 1
Logic Journal of The Igpl / Bulletin of The Igpl, 1998
One of the ways to model contraction functions for belief sets is epistemic entrenchment. The fir... more One of the ways to model contraction functions for belief sets is epistemic entrenchment. The first step was provided by Gärdenfors in , who defined epistemic entrenchment and a contraction function in terms of it and related the latter with the AGM contraction function. Later Hans Rott in presented an entrenchment based contraction function that does not satisfy recovery. In this paper we provide an axiomatic characterization of Rott Contraction. 1
In this paper we adapt the Fermé and Hansson model of Shielded Contraction as well as Hansson et ... more In this paper we adapt the Fermé and Hansson model of Shielded Contraction as well as Hansson et al. Credibilitylimited Revision for belief bases, to join two of the many variations of the AGM model, i.e. those in which knowledge is represented through belief bases instead of logic theories, and those in which the object of the epistemic change does not have priority over the existing information as is the case in the AGM model.
Studia Logica - An International Journal for Symbolic Logic, 1999
We introduce a constructive model of selective belief revision in which it is possible to accept ... more We introduce a constructive model of selective belief revision in which it is possible to accept only a part of the input information. A selective revision operator ο is defined by the equality K ο α = K * f(α), where * is an AGM revision operator and f a function, typically with the property ⊢ α → f(α). Axiomatic characterizations are provided for three variants of selective revision.
ABSTRACT In this paper we provide a characterization of transitively relational maxichoice contra... more ABSTRACT In this paper we provide a characterization of transitively relational maxichoice contraction functions in terms of epistemic entrenchment.
... Santos Departamento de Matemática e Engenharias da Universidade da Madeira alcione@uma.pt Edu... more ... Santos Departamento de Matemática e Engenharias da Universidade da Madeira alcione@uma.pt Eduardo Leopoldo Fermé Departamento ... se nas Teorias da Aprendizagem Situada (Lave & Wenger, 1991; Wenger, 1998; Wenger, McDermott, & Snyder, 2002), ...
Five types of constructions are introduced for non-prioritized belief revision, i.e., belief revi... more Five types of constructions are introduced for non-prioritized belief revision, i.e., belief revision in which the input sentence is not always accepted. These constructions include generalizations of entrenchment-based and sphere-based revision. Axiomatic characterizations are provided, and close interconnections are shown to hold between the di®erent constructions. x1. Introduction. In conventional, AGM-style belief revision [1] the input sentence is always accepted. In non-prioritized belief revision, this requirement is relaxed. Most models of non-prioritized revision operate on belief bases [4,. A couple of proposals for belief sets (theories) have been put forward [3,, but a full treatment including axiomatic characterizations of alternative constructions has been lacking. The purpose of the present paper is to¯ll this gap in the literature by presenting a wide array of alternative constructions and providing axiomatic characterizations that clarify their properties and their interconnections. The intuitive importance of this exercise should be evident; actual agents di®er from the idealized agents of conventional belief change theory in often rejecting inputs that are o®erred for revision.
In this article, we propose an axiomatic characterization for ensconcement-based contraction func... more In this article, we propose an axiomatic characterization for ensconcement-based contraction functions, belief base functions proposed by Williams. We relate this function with other kinds of base contraction functions.
... in K + α = Cn (K ∪ {α})), the agent incorporates a justification or explanation of the ... po... more ... in K + α = Cn (K ∪ {α})), the agent incorporates a justification or explanation of the ... postulates related to the rationality criteria of "minimal change" (for a deep analysis about the ... Let ≤ be an entrenchment ordering on a consistent belief set K that satisfies transitivity, dominance ...
In the logic of theory change, the standard model is AGM, proposed by Alchourrón et al. (J Symb L... more In the logic of theory change, the standard model is AGM, proposed by Alchourrón et al. (J Symb Log 50:510–530, 1985). This paper focuses on the extension of AGM that accounts for contractions of a theory by a set of sentences instead of only by a single sentence. Hansson (Theoria 55:114–132, 1989), Fuhrmann and Hansson (J Logic Lang Inf 3:39–74, 1994) generalized Partial Meet Contraction to the case of contractions by (possibly non-singleton) sets of sentences. In this paper we present the possible worlds semantics for partial meet multiple contractions.
Studia Logica - An International Journal for Symbolic Logic, 2003
This paper focuses on the extension of AGM that allows change for a belief base by a set of sente... more This paper focuses on the extension of AGM that allows change for a belief base by a set of sentences instead of a single sentence. In [FH94], Fuhrmann and Hansson presented an axiomatic for Multiple Contraction and a construction based on the AGM Partial Meet Contraction. We propose for their model another way to construct functions: Multiple Kernel Contraction, that is a modification of Kernel Contraction, proposed by Hansson [Han94] to construct classical AGM contractions and belief base contractions. This construction works out the unsolved problem pointed out by Hansson in [Han99, pp. 369].
We propose a new class of multiple contraction operations — the system of spheres-based multiple ... more We propose a new class of multiple contraction operations — the system of spheres-based multiple contractions — which are a generalization of Grove’s system of spheres-based (singleton) contractions to the case of contractions by (possibly non-singleton) sets of sentences. Furthermore, we show that this new class of functions is a subclass of the class of the partial meet multiple contractions.
Embora a Informática seja uma área intelectualmente exigente, muitos conceitos fundamentais preci... more Embora a Informática seja uma área intelectualmente exigente, muitos conceitos fundamentais precisam ser ensinados em relativamente pouco tempo, o que tem conduzido à experimentação de novas abordagens de ensino. Nesta vertente surge o projecto DROIDE e, nomeadamente, o subprojecto DROIDE VIRTUAL, iniciado em Outubro de 2006, cujo objectivo é a utilização de robots como elementos mediadores entre os alunos e a Informática. Os grupos envolvidos nesta investigação, formados por parceiros da Madeira, Açores e Canárias, colaboram virtualmente no desenvolvimento de projectos de robótica, objectivando verificar a validade do uso de robots no ensino de programação num contexto de educação à distância, bem como analisar o papel das competições robóticas na motivação e no desenvolvimento da capacidade de trabalho em equipa.
In this paper we will describe what we have done in order to change students way of working in an... more In this paper we will describe what we have done in order to change students way of working in an AI subject and we will analyse engineering students' activity using robots Lego® Mindstroms Robotic Invention System (RCX and NXT) in AI classes.
Proceedings of the 17th International Workshop on Nonmonotonic Reasoning (NMR), 2018, 2018
Revision operation is the consistent expansion of a theory by a new belief-representing sentence.... more Revision operation is the consistent expansion of a theory by a new belief-representing sentence. We consider that in a paraconsistent setting this desideratum can be accomplished in at least three distinct ways: the output of a revision operation should be either non-trivial or non-contradictory (in general or relative to the new belief). In this paper those distinctions will be explored in the constructive level by showing how the remainder sets could be refined, capturing the key concepts of paraconsistency in a dynamical scenario. These are preliminaries results of a wider project on Paraconsistent Belief Change conduced by the authors.
The 1985 paper by Carlos Alchourrón (1931–1996), Peter Gärdenfors, and David Makinson (AGM), “On ... more The 1985 paper by Carlos Alchourrón (1931–1996), Peter Gärdenfors, and David Makinson (AGM), “On the Logic of Theory Change: Partial Meet Contraction and Revision Functions” was the starting-point of a large and rapidly growing literature that employs formal models in the investigation of changes in belief states and databases. In this review, the first twenty-five years of this development are summarized. The topics covered include equivalent characterizations of AGM operations, extended representations of the belief states, change operators not included in the original framework, iterated change, applications of the model, its connections with other formal frameworks, computatibility of AGM operations, and criticism of the model.
This work elaborates on the connection between partial meet contractions and kernel contractions ... more This work elaborates on the connection between partial meet contractions and kernel contractions in belief change theory. We present a way to define incision functions (used in kernel con- tractions) from selection functions (used in partial meet contractions) and vice versa. Then we make precise under which conditions there are exact correspondences between selection and incision functions so that the
In this paper we adapt the Fermé and Hansson model of Shielded Contraction as well as Hansson et ... more In this paper we adapt the Fermé and Hansson model of Shielded Contraction as well as Hansson et al. Credibilitylimited Revision for belief bases, to join two of the many variations of the AGM model, i.e. those in which knowledge is represented through belief bases instead of logic theories, and those in which the object of the epistemic change does not have priority over the existing information as is the case in the AGM model.
Logic Journal of The Igpl / Bulletin of The Igpl, 2000
In recent papers Krister Segerberg introduced Irrevocable Belief Revision, as closely related to ... more In recent papers Krister Segerberg introduced Irrevocable Belief Revision, as closely related to AGM revision . In this paper we present irrevocable belief revision in terms of an epistemic entrenchment relation. 1
Logic Journal of The Igpl / Bulletin of The Igpl, 1998
One of the ways to model contraction functions for belief sets is epistemic entrenchment. The fir... more One of the ways to model contraction functions for belief sets is epistemic entrenchment. The first step was provided by Gärdenfors in , who defined epistemic entrenchment and a contraction function in terms of it and related the latter with the AGM contraction function. Later Hans Rott in presented an entrenchment based contraction function that does not satisfy recovery. In this paper we provide an axiomatic characterization of Rott Contraction. 1
In this paper we adapt the Fermé and Hansson model of Shielded Contraction as well as Hansson et ... more In this paper we adapt the Fermé and Hansson model of Shielded Contraction as well as Hansson et al. Credibilitylimited Revision for belief bases, to join two of the many variations of the AGM model, i.e. those in which knowledge is represented through belief bases instead of logic theories, and those in which the object of the epistemic change does not have priority over the existing information as is the case in the AGM model.
Studia Logica - An International Journal for Symbolic Logic, 1999
We introduce a constructive model of selective belief revision in which it is possible to accept ... more We introduce a constructive model of selective belief revision in which it is possible to accept only a part of the input information. A selective revision operator ο is defined by the equality K ο α = K * f(α), where * is an AGM revision operator and f a function, typically with the property ⊢ α → f(α). Axiomatic characterizations are provided for three variants of selective revision.
ABSTRACT In this paper we provide a characterization of transitively relational maxichoice contra... more ABSTRACT In this paper we provide a characterization of transitively relational maxichoice contraction functions in terms of epistemic entrenchment.
... Santos Departamento de Matemática e Engenharias da Universidade da Madeira alcione@uma.pt Edu... more ... Santos Departamento de Matemática e Engenharias da Universidade da Madeira alcione@uma.pt Eduardo Leopoldo Fermé Departamento ... se nas Teorias da Aprendizagem Situada (Lave & Wenger, 1991; Wenger, 1998; Wenger, McDermott, & Snyder, 2002), ...
Five types of constructions are introduced for non-prioritized belief revision, i.e., belief revi... more Five types of constructions are introduced for non-prioritized belief revision, i.e., belief revision in which the input sentence is not always accepted. These constructions include generalizations of entrenchment-based and sphere-based revision. Axiomatic characterizations are provided, and close interconnections are shown to hold between the di®erent constructions. x1. Introduction. In conventional, AGM-style belief revision [1] the input sentence is always accepted. In non-prioritized belief revision, this requirement is relaxed. Most models of non-prioritized revision operate on belief bases [4,. A couple of proposals for belief sets (theories) have been put forward [3,, but a full treatment including axiomatic characterizations of alternative constructions has been lacking. The purpose of the present paper is to¯ll this gap in the literature by presenting a wide array of alternative constructions and providing axiomatic characterizations that clarify their properties and their interconnections. The intuitive importance of this exercise should be evident; actual agents di®er from the idealized agents of conventional belief change theory in often rejecting inputs that are o®erred for revision.
In this article, we propose an axiomatic characterization for ensconcement-based contraction func... more In this article, we propose an axiomatic characterization for ensconcement-based contraction functions, belief base functions proposed by Williams. We relate this function with other kinds of base contraction functions.
... in K + α = Cn (K ∪ {α})), the agent incorporates a justification or explanation of the ... po... more ... in K + α = Cn (K ∪ {α})), the agent incorporates a justification or explanation of the ... postulates related to the rationality criteria of "minimal change" (for a deep analysis about the ... Let ≤ be an entrenchment ordering on a consistent belief set K that satisfies transitivity, dominance ...
In the logic of theory change, the standard model is AGM, proposed by Alchourrón et al. (J Symb L... more In the logic of theory change, the standard model is AGM, proposed by Alchourrón et al. (J Symb Log 50:510–530, 1985). This paper focuses on the extension of AGM that accounts for contractions of a theory by a set of sentences instead of only by a single sentence. Hansson (Theoria 55:114–132, 1989), Fuhrmann and Hansson (J Logic Lang Inf 3:39–74, 1994) generalized Partial Meet Contraction to the case of contractions by (possibly non-singleton) sets of sentences. In this paper we present the possible worlds semantics for partial meet multiple contractions.
Studia Logica - An International Journal for Symbolic Logic, 2003
This paper focuses on the extension of AGM that allows change for a belief base by a set of sente... more This paper focuses on the extension of AGM that allows change for a belief base by a set of sentences instead of a single sentence. In [FH94], Fuhrmann and Hansson presented an axiomatic for Multiple Contraction and a construction based on the AGM Partial Meet Contraction. We propose for their model another way to construct functions: Multiple Kernel Contraction, that is a modification of Kernel Contraction, proposed by Hansson [Han94] to construct classical AGM contractions and belief base contractions. This construction works out the unsolved problem pointed out by Hansson in [Han99, pp. 369].
We propose a new class of multiple contraction operations — the system of spheres-based multiple ... more We propose a new class of multiple contraction operations — the system of spheres-based multiple contractions — which are a generalization of Grove’s system of spheres-based (singleton) contractions to the case of contractions by (possibly non-singleton) sets of sentences. Furthermore, we show that this new class of functions is a subclass of the class of the partial meet multiple contractions.
Embora a Informática seja uma área intelectualmente exigente, muitos conceitos fundamentais preci... more Embora a Informática seja uma área intelectualmente exigente, muitos conceitos fundamentais precisam ser ensinados em relativamente pouco tempo, o que tem conduzido à experimentação de novas abordagens de ensino. Nesta vertente surge o projecto DROIDE e, nomeadamente, o subprojecto DROIDE VIRTUAL, iniciado em Outubro de 2006, cujo objectivo é a utilização de robots como elementos mediadores entre os alunos e a Informática. Os grupos envolvidos nesta investigação, formados por parceiros da Madeira, Açores e Canárias, colaboram virtualmente no desenvolvimento de projectos de robótica, objectivando verificar a validade do uso de robots no ensino de programação num contexto de educação à distância, bem como analisar o papel das competições robóticas na motivação e no desenvolvimento da capacidade de trabalho em equipa.
In this paper we will describe what we have done in order to change students way of working in an... more In this paper we will describe what we have done in order to change students way of working in an AI subject and we will analyse engineering students' activity using robots Lego® Mindstroms Robotic Invention System (RCX and NXT) in AI classes.
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Papers by Eduardo Fermé