Geometric group theory and hyperbolic geometry

在与Papasoglu的合作中，Fujiwara建立了有限呈现群沿细长子群的“jsj分解”理论。这是rip - sela关于jsj -沿循环子群分解定理的推广。如果一个组的所有子组都是有限生成的，那么这个组就是“细长的”。例如，任何有限生成的阿贝尔群和幂零群都是细长的，而秩至少为2的自由群则不是细长的。这本书出版于2006年。

In a joint work with Papasoglu, Fujiwara established a theory of "JSJ-decomposition" for finitely presented group along slender subgroups. The result is a far reach generalization of the theorem by Rips-Sela on the JSJ-decomposition along cyclic subgroups.A group is said "slender" if all of its subgroups are finitely generated. For example, any finitely generated abelian groups and nilpotent groups are slender, while a free group of rank at least two is not slender. The work is published in 2006.