References of "Journal of Logic & Computation"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailModal Extensions of Łukasiewicz Logic for Modeling Coalitional Power
Teheux, Bruno UL; Kroupa, Tomas

in Journal of Logic & Computation (2017), 27(1), 129-154

Modal logics for reasoning about the power of coalitions capture the notion of effectivity functions associated with game forms. The main goal of coalition logics is to provide formal tools for modeling ... [more ▼]

Modal logics for reasoning about the power of coalitions capture the notion of effectivity functions associated with game forms. The main goal of coalition logics is to provide formal tools for modeling the dynamics of a game frame whose states may correspond to different game forms. The two classes of effectivity functions studied are the families of playable and truly playable effectivity functions, respectively. In this paper we generalize the concept of effectivity function beyond the yes/no truth scale. This enables us to describe the situations in which the coalitions assess their effectivity in degrees, based on functions over the outcomes taking values in a finite Łukasiewicz chain. Then we introduce two modal extensions of Łukasiewicz finite-valued logic together with many-valued neighborhood semantics in order to encode the properties of many-valued effectivity functions associated with game forms. As our main results we prove completeness theorems for the two newly introduced modal logics. [less ▲]

Detailed reference viewed: 113 (14 UL)
Full Text
Peer Reviewed
See detailPrioritized Norms in Formal Argumentation
Liao, Beishui UL; Oren, Nir; van der Torre, Leon UL et al

in Journal of Logic & Computation (2017), abs/1709.08034

To resolve conflicts among norms,various nonmonotonic formalisms can be used to perform prioritized normative reasoning. Meanwhile, formal argumentation provides a way to represent nonmonotonic logics. In ... [more ▼]

To resolve conflicts among norms,various nonmonotonic formalisms can be used to perform prioritized normative reasoning. Meanwhile, formal argumentation provides a way to represent nonmonotonic logics. In this paper, we propose a representation of prioritized normative reasoning by argumentation. Using hierarchical abstract normative systems, we define three kinds of prioritized normative reasoning approaches, called Greedy, Reduction, and Optimization. Then, after formulating an argumentation theory for a hierarchical abstract normative system, we show that for a totally ordered hierarchical abstract normative system, Greedy and Reduction can be represented in argumentation by applying the weakest link and the last link principles respectively, and Optimization can be represented by introducing additional defeats capturing implicit conflicts between arguments. [less ▲]

Detailed reference viewed: 55 (5 UL)
Full Text
Peer Reviewed
See detailAccumulative knowledge under bounded resources
Jamroga, Wojciech; Tabatabaei, Masoud UL

in Journal of Logic & Computation (2015)

Detailed reference viewed: 69 (1 UL)
Full Text
Peer Reviewed
See detailAttack-Defense Trees
Kordy, Barbara UL; Mauw, Sjouke UL; Radomirovic, Sasa UL et al

in Journal of Logic & Computation (2012)

Attack-defense trees are a novel methodology for graphical security modeling and assessment. They extend the well known formalism of attack trees by allowing nodes that represent defensive measures to ... [more ▼]

Attack-defense trees are a novel methodology for graphical security modeling and assessment. They extend the well known formalism of attack trees by allowing nodes that represent defensive measures to appear at any level of the tree. This enlarges the modeling capabilities of attack trees and makes the new formalism suitable for representing interactions between an attacker and a defender. Our formalization supports different semantical approaches for which we provide usage scenarios. We also formalize how to quantitatively analyze attack and defense scenarios using attributes. [less ▲]

Detailed reference viewed: 161 (14 UL)
Full Text
Peer Reviewed
See detailComputer-Aided Decision-Making with Trust Relations and Trust Domains (Cryptographic Applications)
Kramer, Simon UL; Goré, Rajeev; Okamoto, Eiji

in Journal of Logic & Computation (2012)

We propose generic declarative definitions of individual and collective trust relations between interacting agents and agent collections, and trust domains of trust-related agents in distributed systems ... [more ▼]

We propose generic declarative definitions of individual and collective trust relations between interacting agents and agent collections, and trust domains of trust-related agents in distributed systems. Our definitions yield (1) (in)compatibility, implicational and transitivity results for trust relationships, including a Datalog-implementability result for their logical structure; (2) computational complexity results for deciding potential and actual trust relationships and membership in trust domains; (3) a positive (negative) compositionality result for strong (weak) trust domains; (4) a computational design pattern for building up strong trust domains; and (5) a negative scalability result for trust domains in general. We instantiate our generic trust concepts in five major cryptographic applications of trust, namely: Access Control, Trusted Third Parties, the Web of Trust, Public-Key Infrastructures and Identity-Based Cryptography. We also show that accountability induces trust. Our defining principle for weak and strong trust (domains) is (common) belief in and (common) knowledge of agent correctness, respectively. [less ▲]

Detailed reference viewed: 22 (0 UL)
See detailReliable Methods of Judgement Aggregation
Hartmann, Stephan; Pigozzi, Gabriella UL; Sprenger, Jan

in Journal of Logic & Computation (2010), 20(2), 603617

The aggregation of consistent individual judgements on logically interconnected propositions into a collective judgement on the same propositions has recently drawn much attention. Seemingly reasonable ... [more ▼]

The aggregation of consistent individual judgements on logically interconnected propositions into a collective judgement on the same propositions has recently drawn much attention. Seemingly reasonable aggregation procedures, such as propositionwise majority voting, cannot ensure an equally consistent collective conclusion. The literature on judgement aggregation refers to such a problem as the discursive dilemma. In this article we assume that the decision which the group is trying to reach is factually right or wrong. Hence, we address the question of how good various approaches are at selecting the right conclusion. We focus on two approaches: distance-based procedures and a Bayesian analysis. They correspond to group-internal and group external decision making, respectively. We compare those methods in a probabilistic model whose assumptions are subsequently relaxed. Our findings have two general implications for judgement aggregation problems: first, in a voting procedure, reasons should carry higher weight than the conclusion, and second, considering members of an advisory board to be highly competent is a better strategy than discounting their advice. [less ▲]

Detailed reference viewed: 43 (0 UL)
Full Text
Peer Reviewed
See detailA Sound and Complete Deductive System for CTL Verification
Gabbay, Dov M. UL; Pnueli, A.

in Journal of Logic & Computation (2008), 16(6), 499536

Detailed reference viewed: 36 (0 UL)
Full Text
Peer Reviewed
See detailCut-Based Abduction
D'Agostino, G.-C.; Gabbay, Dov M. UL

in Journal of Logic & Computation (2008), 16(6), 537560

In this paper we explore a generalization of traditional abduction which can simultaneously perform two different tasks: (i) given an unprovable sequent G, find a sentence H such that, H G is provable ... [more ▼]

In this paper we explore a generalization of traditional abduction which can simultaneously perform two different tasks: (i) given an unprovable sequent G, find a sentence H such that, H G is provable (hypothesis generation); (ii) given a provable sequent G, find a sentence H such that H and the proof of , H G is simpler than the proof of G (lemma generation). We argue that the two tasks should not be distinguished,and present a general procedure for indingsuitable hypotheses or lemmas. When the original sequent is provable, the abduced formula can be seen asa cut formula with respect to Gentzen's sequent calculus, so the abduction method is cut-based. Our method is based on the tableau-like system KE and we argue for its advantages over existing abduction methods based on traditional Smullyan-styleTableaux. [less ▲]

Detailed reference viewed: 19 (0 UL)