decidability

James (Ben) Worrell gave a keynote talk on algorithmic analysis of dynamical systems at the 48th ACM SIGPLAN Symposium on Principles of Programming Languages (POPL 2021). During his talk, Ben presented some of our ongoing work on inequality decision problems for low-order holonomic sequences (see here).

Slides on minimality and positivity for second-order holonomic sequences. Variations given at Mathematical Foundations of Computer Science 2021 (MFCS, Tallinn), the joint Forsyte (TU Wien) and Institute of Science & Technology Seminar, and the Open University Dynamical Systems Seminar.

Joël Ouaknine gave an invited talk on holonomic techniques, periods, and decision problems at Foundations of Software Technology and Theoretical Computer Science conference (FSTTCS 2020). During his talk Joël presented some of our ongoing work on inequality decision problems for low-order holonomic sequences (see here).

The Skolem Problem asks, given a linear recurrence sequence $(u_n)$, whether there exists $n\in\mathbb{N}$ such that $u_n = 0$. In this …

The Markov Reachability Problem We are interested in decision problems for Markov chains and in particular, the Markov Reachability Problem. Given a stochastic matrix $K\in\mathbb{Q}^{d\times d}$ and positive $r\in\mathbb{Q}$, determine whether there exist an $n\in\mathbb{N}$ such that $K^n(1,2)=r$.