Computational Limits and Complexity in Automata, Dynamical Systems, and Geometry

Report on Current Developments in the Research Area

General Direction of the Field

The recent advancements in the research area have been marked by a significant shift towards exploring the computational limits and complexities of various models and systems, particularly in the context of automata theory, dynamical systems, and geometric tiling problems. The field is witnessing a surge in interest in understanding the inherent computational challenges posed by these systems, often leading to undecidable or NP-hard problems. This trend is driven by the need to establish fundamental bounds on the complexity of decision problems, which is crucial for both theoretical insights and practical applications in areas such as complex systems, biological evolution, and computational geometry.

One of the key themes emerging is the application of advanced computational techniques to generalize and extend known results in automata theory. This includes the study of novel automata models, such as advice and nominal automata, which introduce new dimensions to the classical deterministic finite automata (DFAs). The focus on query learning and combinatorial complexity measures for these models highlights a move towards more nuanced and precise characterizations of computational complexity.

Another prominent direction is the exploration of dynamical systems from a computational perspective. Recent work has delved into the computational complexity of smooth dynamical systems, particularly in relation to their ability to simulate Turing machines. This research underscores the importance of defining robust simulation frameworks and the implications of structural stability on the decidability of halting problems.

Geometric tiling problems continue to be a focal point, with new undecidability results being established for increasingly complex tile sets. These results not only extend previous work but also highlight the robustness of undecidability in various geometric settings, reinforcing the notion that certain fundamental problems in this domain remain intractable.

The study of biological evolution through the lens of computational dynamics is also gaining traction. Researchers are proposing novel frameworks that interpret biological complexification as an open-ended generation of computational novelty, suggesting a deeper connection between biological evolution and computation theory.

Noteworthy Papers

  • Rice-like complexity lower bounds for Boolean and uniform automata networks: This work establishes significant complexity lower bounds for automata networks, particularly in the context of non-trivial monadic second-order logic questions, marking a substantial advancement in understanding the computational limits of these systems.

  • Query Learning of Advice and Nominal Automata: The paper introduces new query learning bounds for advice and nominal automata, providing qualitatively different results compared to classical DFAs, and thus expanding the theoretical toolkit for studying these generalized automata models.

  • Computational Dynamical Systems: This study offers a comprehensive framework for understanding the computational complexity of dynamical systems, particularly in relation to their ability to simulate Turing machines, highlighting the importance of structural stability in these simulations.

  • Biological arrow of time: Emergence of tangled information hierarchies and self-modelling dynamics: The paper presents a novel computational-theoretic interpretation of biological evolution, suggesting a meta-simulation framework that could underpin the biological arrow of time, offering a fresh perspective on evolutionary dynamics.

Sources

Rice-like complexity lower bounds for Boolean and uniform automata networks

Ants on the highway

Query Learning of Advice and Nominal Automata

Tiling with Three Polygons is Undecidable

Computational Dynamical Systems

Decision problems on geometric tilings

Biological arrow of time: Emergence of tangled information hierarchies and self-modelling dynamics

On Randomized Computational Models and Complexity Classes: a Historical Overview

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