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.  weiterlesen