4 results
Nathanaël Fijalkow ; Hugo Gimbert ; Edon Kelmendi ; Youssouf Oualhadj.
The value 1 problem is a decision problem for probabilistic automata over finite words: given a probabilistic automaton, are there words accepted with probability arbitrarily close to 1? This problem was proved undecidable recently; to overcome this, several classes of probabilistic automata of […]
Published on June 23, 2015
Nathanaël Fijalkow ; Stefan Kiefer ; Mahsa Shirmohammadi.
Given two labelled Markov decision processes (MDPs), the trace-refinement problem asks whether for all strategies of the first MDP there exists a strategy of the second MDP such that the induced labelled Markov chains are trace-equivalent. We show that this problem is decidable in polynomial time if […]
Published on June 3, 2020
Thomas Colcombet ; Nathanaël Fijalkow ; Pierre Ohlmann.
Bertrand et al. introduced a model of parameterised systems, where each agent is represented by a finite state system, and studied the following control problem: for any number of agents, does there exist a controller able to bring all agents to a target state? They showed that the problem is […]
Published on November 24, 2021
Thomas Colcombet ; Nathanaël Fijalkow ; Florian Horn.
We consider two-player games over graphs and give tight bounds on the memory size of strategies ensuring safety objectives. More specifically, we show that the minimal number of memory states of a strategy ensuring a safety objective is given by the size of the maximal antichain of left quotients […]
Published on January 29, 2024