6th Pacific Workshop on Discrete Mathematics November 27 (Tuesday) ～ 30 (Friday) 2018

Hawaii Tokai International College, Room A130 (Glen Grant Theater) 91-971 Farrington Highway, Kapolei, Hawaii 96707, USA http://htic.pr.tokai.ac.jp/newcampus/index.html

November 27 (Tuesday) 10:30～11:30 Invited Talk Akira Saito* () Guantao Chen (Georgia State University) Shuya Chiba ( University) Ronald J. Gould (Emory University), Xiaofeng Gu (University of West Georgia) Masao Tsugaki Tomoki Yamashita (Kindai University) Spanning bipartite graphs with high degree sum in graphs 13:00~14:00 Invited Talk Songling Shan（Illinois State University） Chvatal's toughness conjecture and related problems 14:05~14:30 Michitaka Furuya (Kitasato University) Shoichi Tsuchiya* () Large homeomorphically irreducible trees in path-free graphs 14:30~14:55 Katsuhiro Ota () Spanning plane subgraphs of 1-plane graphs

November 28 (Wednesday) 10:30～11:30 Kiyoshi Ando (National Institute of Informatics) Some local conditions for k-contractible edeges 13:00~13:25 Shun-ichi Maezawa (Yokohama National University) Haruhide Matsuda* (Shibaura Institute of Technology) Berge-Tutte-type formula for maximum trees with constraints on the leaf degree 13:30~13:55 Shogo Hiro (Keio University) Partition property for colored graphs

14:00~14:25 Yusuke Suzuki* () Gen Kawatani ( University of Science) Partially broken orientations of Eulerian plane graphs 14:30~14:55 Hirotaka Ono* () Hisato Yamanaka ( Nagoya University) An approximation algorithm for L(2; 1)-labeling of unit disk graphs

November 29 (Thursday) 10:30~10:55 Katsuhisa Yamanaka (Iwate University) Yasuko Matsui* (Tokai University) Shin-ichi Nakano (Gunma University) Enumerating all spanning subgraphs with edge-connectivity at least k 11:00~11:25 Yutaro Fukagawa* (Keio University), Katsuhiro Ota (Keio University) Roman dominating sequences in graphs 11:30~11:55 Shun-ichi Maezawa (Yokohama National University) Ryota Matsubara*(Shibaura Institute of Technology) Haruhide Matsuda (Shibaura Institute of Technology) Degree conditions for a graph to have a spanning tree with few branch vertices and leaves 13:30～15:00 Discussion

November 30 (Friday) 10:30~10:55 Morimasa Tsuchiya (Tokai University) Kuniharu Yokomura* (Tokai University Junior College) On p-competition graphs of loopless Hamilton digraphs without symmetric arcs in terms of vertex contraction 11:00~11:25 Gen Kawatani* (Tokyo University of Science) Kenta Ozeki (Yokohama National University) Clockwise labeling of plane regular graphs 11:30~11:55 Shin-ichiro Tashiro (Tokai University) Kenjiro Ogawa (Tokai University) Morimasa Tsuchiya* (Tokai University) On double maximal graphs 13:30～15:00 Discussion