## New answers tagged modules

0
votes

### Exact sequences with two FL-modules

Yes, this is true.
Let $K_0(R)$ be the Grothendieck group of $R$ and $\widetilde K_0(R)=K_0(R)/\langle [R]\rangle$.
Then $[P]=0$ in $\widetilde K_0(R)$ if and only if $P$ is stably free.
For any $...

7
votes

### How to make Ext and Tor constructive?

Jarl Flaten and I have developed the theory of Ext groups constructively in homotopy type theory, and have formalized most of the results in Coq. We use Yoneda's resolution-free approach to Ext, so ...

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