Author name cluster

Fengkui Ju

Possible papers associated with this exact author name in Arrow. This page groups case-insensitive exact name matches and is not a full identity disambiguation profile.

6 papers

1 author row

LORI Conference 2025 Conference Paper

Next-Time Coalition Logic

Thomas Ågotnes
Fengkui Ju

Abstract Coalition Logic (CL) can be seen as the next-time fragment of Alternating-time Temporal Logic (ATL). Modalities in ATL are combinations of strategy quantifiers and tense modalities “glued” together. In ATL* this requirement is relaxed, and the two types of modalities can be mixed freely, resulting in more expressive logics. That comes at a cost: for example, as far as we know, no complete axiomatisation of ATL* exists. In this paper we study the next-time fragment of ATL*: CL*. Like in ATL and unlike in CL, we must now consider strategies rather than just actions, and like in ATL* but unlike in ATL, it matters whether we use full-memory or just memoryless strategies. The question of whether CL* actually is more expressive than CL hinges on that choice. We characterise the relative expressive power of the two variants of CL* compared to CL, and give a sound and complete axiomatisation of CL* with full-memory strategies.

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LORI Conference 2019 Conference Paper

Towards a Logic for Conditional Local Strategic Reasoning

Valentin Goranko
Fengkui Ju

Abstract We consider systems of rational agents who act in pursuit of their individual and collective objectives and we study the reasoning of an agent or an external observer about the consequences from the expected choices of action of the other agents based on their objectives, in order to assess the reasoner’s ability to achieve his own objective. To formalize such reasoning we introduce new modal operators of conditional strategic reasoning and use them to extend Coalition Logic in order to capture variations of conditional strategic reasoning. We provide formal semantics for the new conditional strategic operators, introduce the matching notion of bisimulation for each of them and discuss and compare briefly their expressiveness.

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LORI Conference 2017 Conference Paper

A Dynamic Approach to Temporal Normative Logic

Fengkui Ju
Gianluca Grilletti

Abstract State commands refer to states, not actions. They have a temporal dimension explicitly or implicitly. They indirectly change what we are permitted, forbidden or obligated to do. This paper presents \({{\mathrm{\mathsf {DTNL}}}}{}\), a deontic logic meant to handle state commands based on the branching-time temporal logic \(\mathsf {PCTL}^*\). The models of \({{\mathrm{\mathsf {DTNL}}}}{}\) are trees with bad states, which are identified by a propositional constant \(\mathfrak {b}\) introduced in the language. To model state commands, a dynamic operator that adds states to the extension of \(\mathfrak {b}\) is introduced.

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LORI Conference 2015 Conference Paper

Trace Semantics for IPDL

Fengkui Ju
Nana Cui
Shujiao Li

Abstract Other than relation semantics, IPDL, the extension of PDL with intersection of actions, has a natural trace semantics where the interpretation of an action is a set of sequences of states. IPDL in trace semantics can describe paced concurrent games very well. Surprisingly, IPDL can be reduced to a sublanguage of it in which intersection connects only atomic actions.

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LORI Conference 2013 Conference Paper

A Dynamic Deontic Logic Based on Histories

Fengkui Ju
Li Liang

Abstract We aim to present a deontic logic with updates as an extension of Boolean Modal Logic. The features of this logic include the following: (a) deontic relations are defined on sets of finite sequences of states, called histories, and consequently, formulas are evaluated at histories, not states; and (b) it has two dynamic operators, which tend to update the obligation states of agents in different ways. This logic reflects the distinction between the descriptive and prescriptive use of norm sentences.

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LORI Conference 2011 Conference Paper

Update Semantics for Imperatives with Priorities

Fengkui Ju
Fenrong Liu

Abstract Imperatives occur ubiquitously in our social communications. In real life we often get conflicting orders issued by different speakers whose authorities are ranked. We propose a new update semantics to interpret the meaning of imperatives with priorities and illustrate what changes they bring about in the addressee’s cognitive state. The general properties of the semantics, as well as its core philosophical ideas are discussed extensively in this paper.

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