Descriptional Complexity of Formal Systems 20th IFIP WG 1.02 International Conference, DCFS 2018, Halifax, NS, Canada, July 25-27, 2018, Proceedings - Konstantinidis, Stavros; Konstantinidis, Stavros; Pighizzini, Giovanni; Pighizzini, Giovanni (Springer International Publishing : Imprint: Springer, 2018)