报告人简介：

扶先辉，东北师范大学新葡萄8883官网AMG副院长，教授，博士生导师，研究方向为同调代数与K-理论。研究论文发表于Adv. Math.，Proc. Lond. Math. Soc.，J. Algebra，J. Pure Appl. Algebra等数学杂志。主持国家自然科学基金项目4项，其中面上项目2项。

报告简介：

In this talk, we will introduce ideal approximation theory to an extriangulated category. More specifically, we will estalbish ideal versions of Salce's Lemma, Christensen's Lemma, wakamatsu's Lemma in an extriangulated categories, and show that the intersection of two special precovering (respectively, preenveloping) ideals is still special precovering (respectively, preenveloping). Note that lacking of univerasal properties of pushouts and pullbacks become an obstacle in the proofs of the main results. In this talk, we will proof a rather simple but very useful result on homotopy cartesian which will help us to overcome this obstacle.