Trianglated categories and derived categories are two thing I heard but do not learn for sake of short in motivations.
In this semester, I take a course called homological algebra and I was asked to talk about trianglated categories and derived categories, so I just want to know what is it by this chance. What's more, I draw as much comm. diagram as I can to illustrate the main point, I think you can read it even if you cannot distinguish left-right or row-column (like me). Here is the notes on them---forgive my poor english gramma and the numerous typos.
Last but no mean least, Happy Chineses National Day! (It seems to be late but it is still Oct.1st here)
Xiong Rui
Oct 1st 2019
at St. Peterburg