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12 votes
1 answer
2k views

Why does K-theory need schemes to be Noetherian?

The definition of K-theory of a scheme $X$ is defined as $G_i(X):=K_i(\mathrm{Coh}(X))$ or $K_i(X):=K_i(\mathrm{Vec}(X))$. But usually the schemes are required to be (at least locally) Noetherian, and ...
Li Guanyu's user avatar
  • 449
7 votes
2 answers
2k views

Local property of split exact sequence

In the module category of a ring $A$, is a short exact sequence split if and only if the localization of this sequence is split for every prime ideal? Thanks!
Jian's user avatar
  • 496
5 votes
1 answer
571 views

Perfect chain complexes

In Thomason-Trobaugh in Remark 2.4.4 it is written: "On a general scheme, the perfect complexes are locally finitely presented objects in the "homotopy stack" of derived categories." I was wondering ...
Anette's user avatar
  • 595