研究期間:10108~10207;In this project we will investigate ω-stage Euclidean rings in some depth. As with Euclidean rings, rings admitting a restricted Nagata’s pairwise algorithm and 2-stage Euclidean rings, we will try to develop the appropriate Motzkin-type sets for ω-stage Euclidean rings. Another target of this project is to discover more principal ideal rings which are ω-stage Euclidean but not Euclidean.