Theoretical Aspects of Computing – ICTAC 2021

This book constitutes the proceedings of the 18th International Colloquium on Theoretical Aspects of Computing, ICTAC 2021, organized by the Nazarbayev University, Nur-Sultan, Kazakhstan. The event was supposed to take place in Nur-Sultan, Kazakhstan, but due to COVID-19 pandemic is was held virtually. The 15 papers presented in this volume were carefully reviewed and selected from 40 submissions. The book also contains one invited talk in full paper length. The book deals with challenges in bot