This book constitutes the refereed proceedings of the 15th International Workshop of Descriptional Complexity of Formal Systems, DCFS 2013, held in London, ON, Canada, in July 2013. The 22 revised full papers presented together with 4 invited papers were carefully reviewed and selected from 46 submissions. The topics covered are automata, grammars, languages and other formal systems; various modes of operations and complexity measures; co-operating systems; succinctness of description of objects, state-explosion-like phenomena; circuit complexity of Boolean functions and related measures; size complexity and structural complexity of formal systems; trade-offs between computational models and mode of operation; applications of formal systems; for instance in software and hardware testing, in dialogue systems, in systems modeling or in modeling natural languages; and their complexity constraints; size or structural complexity of formal systems for modeling natural languages; complexity aspects related to the combinatorics of words; descriptional complexity in resource-bounded or structure-bounded environments; structural complexity as related to descriptional complexity; frontiers between decidability and undecidability; universality and reversibility; nature-motivated (bio-inspired) architectures and unconventional models of computing; Kolmogorov-Chaitin complexity, algorithmic information.

This book constitutes the proceedings of the 22nd International Conference on Descriptional Complexity of Format Systems, DCFS 2020, which was supposed to take place in Vienna, Austria, in August 2020, but the conference was canceled due to the COVID-19 crisis. The 19 full papers presented in this volume were carefully reviewed and selected from 31 submissions. They deal with all aspects of descriptional complexity and costs of description of objects in various computational models, such as Turing machines, pushdown automata, finite automata, grammars, and others.

This book constitutes the refereed proceedings of the 16th International Conference on Descriptional Complexity of Formal Systems, DCFS 2014, held in Turku, Finland, in August 2014. The 27 full papers presented were carefully reviewed and selected from 35 submissions. The conference dealt with the following topics: Automata, grammars, languages and other formal systems; various modes of operation and complexity measures; trade-offs between computational models and modes of operation; succinctness of description of objects, state explosion-like phenomena; circuit complexity of Boolean functions and related measures; resource-bounded or structure-bounded environments; frontiers between decidability and undecidability; universality and reversibility; structural complexity; formal systems for applications (e.g., software reliability, software and hardware testing, modeling of natural languages); nature-motivated (bio-inspired) architectures and unconventional models of computing; complexity aspects of combinatorics on words; Kolmogorov complexity.

This book constitutes the proceedings of the 20th International Conference on Descriptional Complexity of Formal Systems, DCFS 2018, held in Halifax, NS, Canada, in July 2018. The 19 full papers presented were carefully reviewed and selected from 24 submissions. DCFS is an annual international working conference concerning the descriptional complexity of formal systems and structures and its applications. Topics of interest are related to all aspects of descriptional complexity and much more.

This book constitutes the proceedings of the 19th International Conference on Descriptional Complexity of Formal Systems, DCFS 2017, held in Milano, Italy, in July 2017. The 20 full papers presented together with 4 invited talks were carefully reviewed and selected from 26 submissions.Descriptional Complexity is a field in Computer Science that deals with the size of all kinds of objects that occur in computational models, such as turing machines, finite automata, grammars, splicing systems and others. The topics of this conference are related to all aspects of descriptional complexity.