scholarly journals Reachability Problems on Reliable and Lossy Queue Automata

2021 ◽  
Author(s):  
Chris Köcher
Keyword(s):  
Polynomial Time ◽  
Reachability Problem ◽  
Single Sequence

AbstractWe study the reachability problem for queue automata and lossy queue automata. Concretely, we consider the set of queue contents which are forwards resp. backwards reachable from a given set of queue contents. Here, we prove the preservation of regularity if the queue automaton loops through some special sets of transformation sequences. This is a generalization of the results by Boigelot et al. and Abdulla et al. regarding queue automata looping through a single sequence of transformations. We also prove that our construction is possible in polynomial time.

scholarly journals A Restricted Reachability Problem of Petri Nets Solvable in Pseudo-Polynomial Time

1993 ◽  
Vol 29 (11) ◽  
pp. 1352-1360
Author(s):  
Keiko TAKAHASHI ◽  
Kiyohiko NAKAMURA ◽  
Atsunobu ICHIKAWA
Keyword(s):  
Petri Nets ◽  
Polynomial Time ◽  
Reachability Problem ◽  
Pseudo Polynomial Time

scholarly journals Probabilistic Timed Automata with One Clock and Initialised Clock-Dependent Probabilities

2021 ◽  
Vol Volume 17, Issue 4 ◽  
Author(s):  
Jeremy Sproston
Keyword(s):  
Markov Decision Processes ◽  
Polynomial Time ◽  
Timed Automata ◽  
Decision Processes ◽  
Reachability Problem ◽  
Probabilistic Choice ◽  
Markov Decision ◽  
Affine Functions ◽  
Probabilistic Timed Automata

Clock-dependent probabilistic timed automata extend classical timed automata with discrete probabilistic choice, where the probabilities are allowed to depend on the exact values of the clocks. Previous work has shown that the quantitative reachability problem for clock-dependent probabilistic timed automata with at least three clocks is undecidable. In this paper, we consider the subclass of clock-dependent probabilistic timed automata that have one clock, that have clock dependencies described by affine functions, and that satisfy an initialisation condition requiring that, at some point between taking edges with non-trivial clock dependencies, the clock must have an integer value. We present an approach for solving in polynomial time quantitative and qualitative reachability problems of such one-clock initialised clock-dependent probabilistic timed automata. Our results are obtained by a transformation to interval Markov decision processes.

scholarly journals Checking Robustness Between Weak Transactional Consistency Models

2021 ◽  
pp. 87-117
Author(s):  
Sidi Mohamed Beillahi ◽  
Ahmed Bouajjani ◽  
Constantin Enea
Keyword(s):  
Distributed Systems ◽  
Polynomial Time ◽  
Reduction Theory ◽  
Proof Technique ◽  
Reachability Problem ◽  
Snapshot Isolation ◽  
Trade Offs ◽  
Consistency Model ◽  
Causal Consistency ◽  
Consistency Models

AbstractConcurrent accesses to databases are typically encapsulated in transactions in order to enable isolation from other concurrent computations and resilience to failures. Modern databases provide transactions with various semantics corresponding to different trade-offs between consistency and availability. Since a weaker consistency model provides better performance, an important issue is investigating the weakest level of consistency needed by a given program (to satisfy its specification). As a way of dealing with this issue, we investigate the problem of checking whether a given program has the same set of behaviors when replacing a consistency model with a weaker one. This property known as robustness generally implies that any specification of the program is preserved when weakening the consistency. We focus on the robustness problem for consistency models which are weaker than standard serializability, namely, causal consistency, prefix consistency, and snapshot isolation. We show that checking robustness between these models is polynomial time reducible to a state reachability problem under serializability. We use this reduction to also derive a pragmatic proof technique based on Lipton’s reduction theory that allows to prove programs robust. We have applied our techniques to several challenging applications drawn from the literature of distributed systems and databases.

The 2-closure of a 32-transitive group in polynomial time

2018 ◽  
Vol 60 (2) ◽  
pp. 360-375
Author(s):  
A. V. Vasil'ev ◽  
D. V. Churikov
Keyword(s):  
Polynomial Time ◽  
Transitive Group

Learning Importance of Preferences

10.29007/v68w ◽  
2018 ◽  
Author(s):  
Ying Zhu ◽  
Mirek Truszczynski
Keyword(s):  
Polynomial Time ◽  
Polynomial Time Algorithm ◽  
Time Algorithm ◽  
Scoring Rules ◽  
Np Hard ◽  
Individual Preferences

We study the problem of learning the importance of preferences in preference profiles in two important cases: when individual preferences are aggregated by the ranked Pareto rule, and when they are aggregated by positional scoring rules. For the ranked Pareto rule, we provide a polynomial-time algorithm that finds a ranking of preferences such that the ranked profile correctly decides all the examples, whenever such a ranking exists. We also show that the problem to learn a ranking maximizing the number of correctly decided examples (also under the ranked Pareto rule) is NP-hard. We obtain similar results for the case of weighted profiles when positional scoring rules are used for aggregation.

scholarly journals Learn your opponent's strategy (in polynomial time)!

1996 ◽  
pp. 164-176 ◽  
Author(s):  
Yishay Mor ◽  
Claudia V. Goldman ◽  
Jeffrey S. Rosenschein
Keyword(s):  
Polynomial Time
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