Credibility limited revision

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 different constructions.info:eu-repo/semantics/publishedVersio

System of Spheres-based Two Level Credibility-limited Revisions

Two level credibility-limited revision is a non-prioritized revision operation. When revising by a two level credibility-limited revision, two levels of credibility and one level of incredibility are considered. When revising by a sentence at the highest level of credibility, the operator behaves as a standard revision, if the sentence is at the second level of credibility, then the outcome of the revision process coincides with a standard contraction by the negation of that sentence. If the sentence is not credible, then the original belief set remains unchanged. In this paper, we propose a construction for two level credibility-limited revision operators based on Grove's systems of spheres and present an axiomatic characterization for these operators.Comment: In Proceedings TARK 2023, arXiv:2307.0400

Two level credibility-limited revisions

In this paper, we propose a new kind of nonprioritized operator which we call two level credibility-limited revision. When revising through a two level credibility-limited revision there are two levels of credibility and one of incredibility. When revising by a sentence at the highest level of credibility, the operator behaves as a standard revision, if the sentence is at the second level of credibility, then the outcome of the revision process coincides with a standard contraction by the negation of that sentence. If the sentence is not credible, then the original belief set remains unchanged. In this article, we axiomatically characterize several classes of two level credibility-limited revision operators.info:eu-repo/semantics/publishedVersio

Studies in credibility: limited base revision

In this paper we present axiomatic characterizations for several classes of credibility-limited base revision functions and establish the interrelation among those classes. We also propose and axiomatically characterize two new base revision functions.info:eu-repo/semantics/publishedVersio

Credibility-limited base revision: new classes and their characterizations

In this paper we study a kind of operator —known as credibility-limited base revisions— which addresses two of the main issues that have been pointed out to the AGM model of belief change. Indeed, on the one hand, these operators are defined on belief bases (rather than belief sets) and, on the other hand, they are constructed with the underlying idea that not all new information is accepted. We propose twenty different classes of credibility limited base revision operators and obtain axiomatic characterizations for each of them. Additionally we thoroughly investigate the interrelations (in the sense of inclusion) among all those classes. More precisely, we analyse whether each one of those classes is or is not (strictly) contained in each of the remaining ones.info:eu-repo/semantics/publishedVersio

Levi and Harper identities for non-prioritized belief base change

In this paper, we investigate the relation between shielded base contraction postulates and credibility-limited (CL) base revision postulates. More precisely, we identify (i) the relation between the postulates satisfied by a shielded base contraction operator and the postulates satisfied by the CL base revision operator that is defined from it by means of the consistency-preserving Levi identity and (ii) the relation between the postulates satisfied by a CL base revision operator and the postulates satisfied by the shielded base contraction operator that is defined from it by means of the Harper identity. Furthermore, we show that the consistency-preserving Levi identity and the Harper identity establish a one-to one correspondence between the twenty classes of shielded base contractions presented in [21] and the twenty classes of credibility-limited base revisions presented in [22].info:eu-repo/semantics/publishedVersio

"Obedient Servant or Runaway Eurocracy? Delegation, Agency, and Agenda Setting in the European Community"

Do supranational institutions matter - do they deserve the status of an independent causal variable - in EC policymaking? Does the Commission matter? Does the European Court of Justice? Does the European Parliament? Is the European Community characterized by continued member state dominance, or by a runaway Commission and an activist Court progressively chipping away at this dominance? These are some of the most important questions for our understanding of the European Community and of European integration, and have divided the two traditional schools of thought in regional integration, with neofunctionalists [Haas 1958; Lindberg & Scheingold 1970] generally asserting, and intergovernmentalists [Hoffmann 1966; Taylor 1983; Moravcsik 1991, 1993] generally denying, any important causal role for supranational institutions in the integration process. By and large, however, neither neofunctionalism nor intergovernmentalism1 has generated testable hypotheses regarding the conditions under which, and the ways in which, supranational institutions exert an independent causal influence on either EC governance or the process of European integration. This paper presents a unified theoretical approach to the problem of supranational influence, based largely on the new institutionalism in rational choice theory. Simplifying only slightly, this new literature can be traced to Shepsle's [1979] pioneering work on the role of institutions in the US Congress. Beginning with the observation by McKelvey [1976], Riker [1980] and others that, in a system of majoritarian decisionmaking, policy choices are inherently unstable, "cycling" among multiple possible equilibria, Shepsle argued that Congressional institutions, and in particular the committee system, could produce structure-induced equilibrium, by ruling some policy alternatives as permissible or impermissible, and by structuring the voting and veto power of the various actors in the decisionmaking process

Regional variations in standards – problem or opportunity?

A preliminary analysis and evaluation is made of the differences between the various organic standards and of the different implementation rules of the EU Regulation 2092/91 in Europe. This is part of an EU-funded project on the revision of this regulation. These preliminary results show that many differences have specific justifications, which are strongly influenced by specific national or regional circumstances or policy environment. The potential for more regional variation is discusse

Plausible inference: A multi-valued logic for problem solving

A new logic is developed which permits continuously variable strength of belief in the truth of assertions. Four inference rules result, with formal logic as a limiting case. Quantification of belief is defined. Propagation of belief to linked assertions results from dependency-based techniques of truth maintenance so that local consistency is achieved or contradiction discovered in problem solving. Rules for combining, confirming, or disconfirming beliefs are given, and several heuristics are suggested that apply to revising already formed beliefs in the light of new evidence. The strength of belief that results in such revisions based on conflicting evidence are a highly subjective phenomenon. Certain quantification rules appear to reflect an orderliness in the subjectivity. Several examples of reasoning by plausible inference are given, including a legal example and one from robot learning. Propagation of belief takes place in directions forbidden in formal logic and this results in conclusions becoming possible for a given set of assertions that are not reachable by formal logic

Gateway Modeling and Simulation Plan

This plan institutes direction across the Gateway Program and the Element Projects to ensure that Cross Program M&S are produced in a manner that (1) generate the artifacts required for NASA-STD-7009 compliance, (2) ensures interoperability of M&S exchanged and integrated across the program and, (3) drives integrated development efforts to provide cross-domain integrated simulation of the Gateway elements, space environment, and operational scenarios. This direction is flowed down via contractual enforcement to prime contractors and includes both the GMS requirements specified in this plan and the NASASTD- 7009 derived requirements necessary for compliance. Grounding principles for management of Gateway Models and Simulations (M&S) are derived from the Columbia Accident Investigation Board (CAIB) report and the Diaz team report, A Renewed Commitment to Excellence. As an outcome of these reports, and in response to Action 4 of the Diaz team report, the NASA Standard for Models and Simulations, NASA-STD-7009 was developed. The standard establishes M&S requirements for development and use activities to ensure proper capture and communication of M&S pedigree and credibility information to Gateway program decision makers. Through the course of the Gateway program life cycle M&S will be heavily relied upon to conduct analysis, test products, support operations activities, enable informed decision making and ultimately to certify the Gateway with an acceptable level of risk to crew and mission. To reduce risk associated with M&S influenced decisions, this plan applies the NASA-STD-7009 requirements to produce the artifacts that support credibility assessments and ensure the information is communicated to program management