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Temporal Logic of Causal Knowledge
 Proc. of WoLLiC '98
, 1998
"... . Temporal logic of causal knowledge over general partially ordered structures is defined. The definition of knowledge captures the change of state due to action executions. The structures are a variant of flow event structures including prime event structures and branching processes of Petri Ne ..."
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. Temporal logic of causal knowledge over general partially ordered structures is defined. The definition of knowledge captures the change of state due to action executions. The structures are a variant of flow event structures including prime event structures and branching processes of Petri Nets. Modalities corresponding to the causality, independency, and indistinguishability relations are used. Formulas are interpreted over local state occurrences. The logic is proved to be decidable and a complete axiomatization is provided. Keywords: multiagent systems, knowledge, temporal logic, causality, partially ordered sets. 1 Introduction Reasoning about knowledge is one of the fundamental problems in multiagent systems. Usually, dynamic global state spaces partitioned w.r.t. the agents' information are considered [3]. In the theory of distributed systems, knowledge formulas are interpreted over infinite linear or branching runs of the systems [4, 5, 3, 9, 15, 16]. It is clear ...
The MSO Theory of Connectedly Communicating Processes
"... Abstract. We identify a network of sequential processes that communicate by synchronizing frequently on common actions. More precisely, we demand that there is a bound k such that if the process p executes k steps without hearing from process q—directly or indirectly—then it will neverhearfromq agai ..."
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Cited by 6 (0 self)
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Abstract. We identify a network of sequential processes that communicate by synchronizing frequently on common actions. More precisely, we demand that there is a bound k such that if the process p executes k steps without hearing from process q—directly or indirectly—then it will neverhearfromq again. The noninterleaved branching time behavior of a system of connectedly communicating processes (CCP) is given by its event structure unfolding. We show that the monadic second order (MSO) theory of the event structure unfolding of every CCP is decidable. Using this result, we also show that an associated distributed controller synthesis problem is decidable for linear time specifications that do not discriminate between two different linearizations of the same partially ordered execution.
Modelchecking Trace Event Structures
"... Given a regular collection of Mazurkiewicz traces, which can be seen as the behaviours of a finitestate concurrent system, one can associate with it a canonical regular event structure. This event structure is a single (often infinite) structure that captures both the concurrency and conflict infor ..."
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Cited by 6 (1 self)
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Given a regular collection of Mazurkiewicz traces, which can be seen as the behaviours of a finitestate concurrent system, one can associate with it a canonical regular event structure. This event structure is a single (often infinite) structure that captures both the concurrency and conflict information present in the system. We study the problem of modelchecking such structures against logics such as firstorder logic (F OL), monadic secondorder logic (MSOL) anda new logic that lies in between these two called monadic trace logic (MTL). MTL is a fragment of MSOL where the quantification is restricted to sets that are conflictfree. While it is known that modelchecking such event structuresagainst M SOL is undecidable, our main results are thatF OL and MTL admit effective modelchecking procedures.It turns out that F OL captures previously known decidabletemporal logics on event structures. M TL is more powerful and can express interesting branchingtime properties of event structures, and when restricted to a sequential setting, can express the standard logic C
Temporal Approach to Causal Knowledge
, 2000
"... Temporal logic of causal knowledge over general partially ordered structures of local states is dened. The denition of knowledge captures the change of state due to action executions. The structures are a variant of ow event structures including prime event structures and branching processes of Petr ..."
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Cited by 3 (1 self)
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Temporal logic of causal knowledge over general partially ordered structures of local states is dened. The denition of knowledge captures the change of state due to action executions. The structures are a variant of ow event structures including prime event structures and branching processes of Petri Nets. Modalities corresponding to the causality, concurrency, and indistinguishability relations are used. Formulas are interpreted over local state occurrences. The logic is proved to be decidable and a complete axiomatization is provided. 1 Keywords: multiagent systems, knowledge, temporal logic, causality, partially ordered sets. 1 Introduction Reasoning about knowledge is one of the fundamental problems in multiagent systems. Usually, dynamic global state spaces partitioned w.r.t. the agents' information are considered [5]. In the theory of distributed systems, knowledge formulas are interpreted over innite linear or branching runs of the systems [8, 9, 5, 13, 20, 21]. It is cle...
Model Checking Logics for Communicating Sequential Agents
, 1999
"... . We present a model checking algorithm for LCSA , a temporal logic for communicating sequential agents (CSAs) introduced by Lodaya, Ramanujam, and Thiagarajan. LCSA contains temporal modalities indexed with a local point of view of one agent and allows to refer to properties of other agents accordi ..."
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. We present a model checking algorithm for LCSA , a temporal logic for communicating sequential agents (CSAs) introduced by Lodaya, Ramanujam, and Thiagarajan. LCSA contains temporal modalities indexed with a local point of view of one agent and allows to refer to properties of other agents according to the latest gossip which is related to local knowledge. The model checking procedure relies on a modularisation of LCSA into temporal and gossip modalities. We introduce a hierarchy of formulae and a corresponding hierarchy of equivalences, which allows to compute for each formula and finite state distributed system a finite multi modal Kripke structure, on which the formula can be checked with standard techniques. 1 Introduction A reasonable and lucid way of formally treating distributed systems is to consider them as a fixed collection of sequential components (agents) which can operate independently as well as cooperate by exchanging information. There is an increasing awareness, b...
Model Checking of Causal Knowledge Formulas
, 1999
"... A model checking algorithm for a variant of the temporal logic of causal knowledge [25] is given. The temporal language is interpreted over labelled prime event structures. Knowledge operators express agents' history knowledge and the knowledge acquired about other agents. The temporal modalities co ..."
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A model checking algorithm for a variant of the temporal logic of causal knowledge [25] is given. The temporal language is interpreted over labelled prime event structures. Knowledge operators express agents' history knowledge and the knowledge acquired about other agents. The temporal modalities correspond to the immediate causality and causality. For systems represented by deterministic Asynchronous Automata we prove that the complexity of the model checking algorithm for formula ' over automaton A of Nagents is j'j \Theta jAj \Theta jGA j \Theta 2 O(N 3 logN) , where jGA j is the size of the global state space of A and A is the alphabet of actions. Partial order reductions are used in order to make the model checking algorithm more efficient. 1 Introduction In the theory of distributed systems, knowledge formulas are usually interpreted over infinite linear or branching runs of global states of the systems [12,13,11,16,26,27]. It is clear that capturing changes in state due t...
Towards Formal Specification and Verification in Cyberspace
 5  7 April 2000, NASA Goddard Space Flight
, 2000
"... A formal framework for specification and verification of multiagent systems is developed. Specification of an infrastructure created by a mobile agent platform is presented. On the basis of the specification, the notions of common ontology core, and agent's knowledge are introduced. A simple agent ..."
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Cited by 2 (2 self)
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A formal framework for specification and verification of multiagent systems is developed. Specification of an infrastructure created by a mobile agent platform is presented. On the basis of the specification, the notions of common ontology core, and agent's knowledge are introduced. A simple agent architecture is presented. Given agents' knowledge and decision mechanisms, model checking method is applied to verify whether the agents can realize their goals. 1
Cooperation Mechanisms in a MultiAgent Distributed Environment
 In Proc. ECAI98 Workshop w8
, 1998
"... . In the paper we present our work on design and analysis of agent cooperation in distributed systems. The work is not completed yet, so that some parts of it, especially the formal framework, should be viewed as a preliminary version. Multiagent systems are represented by BDIautomata, i.e., async ..."
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Cited by 1 (1 self)
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. In the paper we present our work on design and analysis of agent cooperation in distributed systems. The work is not completed yet, so that some parts of it, especially the formal framework, should be viewed as a preliminary version. Multiagent systems are represented by BDIautomata, i.e., asynchronous automata composed of nondeterministic agents equipped with mental attitudes like belief, desire, and intentions. These attitudes are acquired by the agents by executing so called mental actions. Behaviours of multiagent systems are represented by prime event structures. The prime event structure when augmented with utility functions defined on the terminal nodes of the structure may be viewed as games in extensive form defined on local states rather than on global states as in the classical definition. The definition of knowledge, in our framework, captures the change of state due to action executions. A notion of local knowledgebased protocols is defined. A game theory method of ...
Local Interactions, Explicit Communication And Causal Knowledge In Games And MultiAgent Systems
"... . In this paper we suggest new structures for modeling games (multiagent systems). We use prime event structures as the branching runs representing all the possible plays in games. Event structures have been already successfully applied in the theory of distributed systems [18] and several temporal ..."
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. In this paper we suggest new structures for modeling games (multiagent systems). We use prime event structures as the branching runs representing all the possible plays in games. Event structures have been already successfully applied in the theory of distributed systems [18] and several temporal logics have adopted them as frames. We show that a prime event structure extended with a utility function defined on the terminal nodes can be naturally considered as distributed game in extensive form. The notion of passing knowledge introduces a novel concept to the standard definition of games in extensive form. As well, the notion of information sets (corresponding to agent's knowledge) gets new insight, because now the information sets cannot be defined in an arbitrary way, i.e., they must correspond to causal dependencies in the system. Key words: Multiagent systems, games, even structures, causality, knowledge. 1 Introduction It is intuitively clear that games are closely relat...
Distributed Games: Local Interactions, Explicit Communication, and Causal Knowledge
, 1998
"... In this paper we suggest new structures for modeling games. We use prime event structures as the branching runs representing all the possible plays in games. Event structures have been already successfully applied in the theory of distributed systems [18] and several temporal logics have adopted the ..."
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In this paper we suggest new structures for modeling games. We use prime event structures as the branching runs representing all the possible plays in games. Event structures have been already successfully applied in the theory of distributed systems [18] and several temporal logics have adopted them as frames. We show that a prime event structure extended with a utility function defined on the terminal nodes can be naturally considered as distributed game in extensive form. The notion of passing knowledge introduces a novel concept to the standard definition of games in extensive form. As well, the notion of information sets (corresponding to agent's knowledge) gets new insight, because now the information sets cannot be defined in an arbitrary way, i.e., they must correspond to causal dependencies in the system. 3 pusta strona 4 1 Introduction It is intuitively clear that games are closely related to distributed systems and multiagent systems. However, the classical definition ...