Free ℤ-module
Futa, Yuichi, Okazaki, Hiroyuki, Shidama, Yasunari
Cell Petri Net Concepts
Jitsukawa, Mitsuru, Kawamoto, Pauline, Shidama, Yasunari, Nakamura, Yatsuka
Convex Sets and Convex Combinations on Complex Linear Spaces
Matsuzaki, Hidenori, Endou, Noboru, Shidama, Yasunari