123,029 research outputs found
Meaning and Dialogue Coherence: A Proof-theoretic Investigation
This paper presents a novel proof-theoretic account of dialogue coherence. It focuses on an abstract class of cooperative information-oriented dialogues and describes how their structure can be accounted for in terms of a multi-agent hybrid inference system that combines natural deduction with information transfer and observation. We show how certain dialogue structures arise out of the interplay between the inferential roles of logical connectives (i.e., sentence semantics), a rule for transferring information between agents, and a rule for information flow between agents and their environment. The order of explanation is opposite in direction to that adopted in game-theoretic semantics, where sentence semantics (or a notion of valid inference) is derived from winning dialogue strategies. That approach and the current one may, however, be reconcilable, since we focus on cooperative dialogue, whereas the game-theoretic tradition concentrates on adversarial dialogue
The game semantics of game theory
We use a reformulation of compositional game theory to reunite game theory
with game semantics, by viewing an open game as the System and its choice of
contexts as the Environment. Specifically, the system is jointly controlled by
noncooperative players, each independently optimising a real-valued
payoff. The goal of the system is to play a Nash equilibrium, and the goal of
the environment is to prevent it. The key to this is the realisation that
lenses (from functional programming) form a dialectica category, which have an
existing game-semantic interpretation.
In the second half of this paper, we apply these ideas to build a compact
closed category of `computable open games' by replacing the underlying
dialectica category with a wave-style geometry of interaction category,
specifically the Int-construction applied to the cartesian monoidal category of
directed-complete partial orders
A Parameterised Hierarchy of Argumentation Semantics for Extended Logic Programming and its Application to the Well-founded Semantics
Argumentation has proved a useful tool in defining formal semantics for
assumption-based reasoning by viewing a proof as a process in which proponents
and opponents attack each others arguments by undercuts (attack to an
argument's premise) and rebuts (attack to an argument's conclusion). In this
paper, we formulate a variety of notions of attack for extended logic programs
from combinations of undercuts and rebuts and define a general hierarchy of
argumentation semantics parameterised by the notions of attack chosen by
proponent and opponent. We prove the equivalence and subset relationships
between the semantics and examine some essential properties concerning
consistency and the coherence principle, which relates default negation and
explicit negation. Most significantly, we place existing semantics put forward
in the literature in our hierarchy and identify a particular argumentation
semantics for which we prove equivalence to the paraconsistent well-founded
semantics with explicit negation, WFSX. Finally, we present a general proof
theory, based on dialogue trees, and show that it is sound and complete with
respect to the argumentation semantics.Comment: To appear in Theory and Practice of Logic Programmin
The Informal Logic of Mathematical Proof
Informal logic is a method of argument analysis which is complementary to
that of formal logic, providing for the pragmatic treatment of features of
argumentation which cannot be reduced to logical form. The central claim of
this paper is that a more nuanced understanding of mathematical proof and
discovery may be achieved by paying attention to the aspects of mathematical
argumentation which can be captured by informal, rather than formal, logic. Two
accounts of argumentation are considered: the pioneering work of Stephen
Toulmin [The uses of argument, Cambridge University Press, 1958] and the more
recent studies of Douglas Walton, [e.g. The new dialectic: Conversational
contexts of argument, University of Toronto Press, 1998]. The focus of both of
these approaches has largely been restricted to natural language argumentation.
However, Walton's method in particular provides a fruitful analysis of
mathematical proof. He offers a contextual account of argumentational
strategies, distinguishing a variety of different types of dialogue in which
arguments may occur. This analysis represents many different fallacious or
otherwise illicit arguments as the deployment of strategies which are sometimes
admissible in contexts in which they are inadmissible. I argue that
mathematical proofs are deployed in a greater variety of types of dialogue than
has commonly been assumed. I proceed to show that many of the important
philosophical and pedagogical problems of mathematical proof arise from a
failure to make explicit the type of dialogue in which the proof is introduced.Comment: 14 pages, 1 figure, 3 tables. Forthcoming in Perspectives on
Mathematical Practices: Proceedings of the Brussels PMP2002 Conference
(Logic, Epistemology and the Unity of the Sciences Series), J. P. Van
Bendegem & B. Van Kerkhove, edd. (Dordrecht: Kluwer, 2004
Budgeted Reinforcement Learning in Continuous State Space
A Budgeted Markov Decision Process (BMDP) is an extension of a Markov
Decision Process to critical applications requiring safety constraints. It
relies on a notion of risk implemented in the shape of a cost signal
constrained to lie below an - adjustable - threshold. So far, BMDPs could only
be solved in the case of finite state spaces with known dynamics. This work
extends the state-of-the-art to continuous spaces environments and unknown
dynamics. We show that the solution to a BMDP is a fixed point of a novel
Budgeted Bellman Optimality operator. This observation allows us to introduce
natural extensions of Deep Reinforcement Learning algorithms to address
large-scale BMDPs. We validate our approach on two simulated applications:
spoken dialogue and autonomous driving.Comment: N. Carrara and E. Leurent have equally contribute
The Dynamic Impact of Periodic Review on Women’s Rights
Human rights treaty bodies have been frequently criticized as useless and the regime’s self-reporting procedure widely viewed as a whitewash. Yet very little research explores what, if any, influence this periodic review process has on governments’ implementation of and compliance with treaty obligations. We argue oversight committees may play an important role in improving rights on the ground by providing information for international and primarily domestic audiences. This paper examines the cumulative effects on women’s rights of self-reporting and oversight review, using original data on the history of state reporting to and review by the Committee on the Elimination of Discrimination against Women (CmEDAW). Using a dynamic approach to study the effects of the periodic review process, we find that self-reporting has a significant positive effect on women’s rights. We explore three clusters of evidence for the domestic mobilization mechanism: information provision through domestic civil society organizations; publicity and critique through the domestic media; and parliamentary attention, debate, and implementation of recommendations. This is the first study to present positive evidence on the effects of self-reporting on rights and to describe the mechanisms that link Geneva bodies with local politics. Our findings challenge the received wisdom that the process of reporting to these treaty bodies is basically useless
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