Positivity problems for low-order linear recurrence sequences

J Ouaknine, J Worrell - Proceedings of the twenty-fifth annual ACM-SIAM …, 2014 - SIAM
We consider two decision problems for linear recurrence sequences (LRS) over the
integers, namely the Positivity Problem (are all terms of a given LRS positive?) and the …

Cost analysis of nondeterministic probabilistic programs

P Wang, H Fu, AK Goharshady, K Chatterjee… - Proceedings of the 40th …, 2019 - dl.acm.org
We consider the problem of expected cost analysis over nondeterministic probabilistic
programs, which aims at automated methods for analyzing the resource-usage of such …

On the Positivity Problem for Simple Linear Recurrence Sequences,

J Ouaknine, J Worrell - International Colloquium on Automata, Languages …, 2014 - Springer
Given a linear recurrence sequence (LRS) over the integers, the Positivity Problem asks
whether all terms of the sequence are positive. We show that, for simple LRS (those whose …

Ultimate positivity is decidable for simple linear recurrence sequences

J Ouaknine, J Worrell - International Colloquium on Automata, Languages …, 2014 - Springer
We consider the decidability and complexity of the Ultimate Positivity Problem, which asks
whether all but finitely many terms of a given rational linear recurrence sequence (LRS) are …

On linear recurrence sequences and loop termination

J Ouaknine, J Worrell - ACM Siglog News, 2015 - dl.acm.org
A sequence of real numbers is said to be positive if all terms are positive, and ultimately
positive if all but finitely many terms are positive. In this article we survey recent progress on …

On the skolem problem and the skolem conjecture

R Lipton, F Luca, J Nieuwveld, J Ouaknine… - Proceedings of the 37th …, 2022 - dl.acm.org
It is a longstanding open problem whether there is an algorithm to decide the Skolem
Problem for linear recurrence sequences (LRS) over the integers, namely whether a given …

Closed forms for numerical loops

Z Kincaid, J Breck, J Cyphert, T Reps - Proceedings of the ACM on …, 2019 - dl.acm.org
This paper investigates the problem of reasoning about non-linear behavior of simple
numerical loops. Our approach builds on classical techniques for analyzing the behavior of …

Reachability problems for Markov chains

S Akshay, T Antonopoulos, J Ouaknine… - Information Processing …, 2015 - Elsevier
We consider the following decision problem: given a finite Markov chain with distinguished
source and target states, and given a rational number r, does there exist an integer n such …

Solving conditional linear recurrences for program verification: the periodic case

C Wang, F Lin - Proceedings of the ACM on Programming Languages, 2023 - dl.acm.org
In program verification, one method for reasoning about loops is to convert them into sets of
recurrences, and then try to solve these recurrences by computing their closed-form …

Approximate verification of the symbolic dynamics of Markov chains

M Agrawal, S Akshay, B Genest… - Journal of the ACM …, 2015 - dl.acm.org
A finite-state Markov chain M can be regarded as a linear transform operating on the set of
probability distributions over its node set. The iterative applications of M to an initial …