Logic Programming and Nonmonotonic Reasoning 15th International Conference, LPNMR 2019, Philadelphia, PA, USA, June 3-7, 2019, Proceedings - Balduccini, Marcello; Balduccini, Marcello; Lierler, Yuliya; Lierler, Yuliya; Woltran, Stefan; Woltran, Stefan (Springer International Publishing : Imprint: Springer, 2019)