超自由象与σ-根

The Transfree image and σ-Radical of Rings

利用范畴理论中上积 (Coproduct)定义一个新概念———超自由象 ,通过它的性质给出σ 根的一个新刻划 ,并且给出低σ 根的一个新构造 .

A new concept, Transfree image, is introduced by means of coproduct in the category of associative rings. A new characterization for σ Radical is represented based on the properties of Transfree image, and a new construction of lower σ Radical is obtained.