McCoy's Rank

Atiyah soln project 2.11

A module over PID is torsion-free if and only if flat

Brun folder

M flat over A -> M*B flat over B

CM

New CM

Localization stuffs

are in Regular Rings.

Hom commuting with tensor

Hom(M,N)*B=Hom(M_B,N_B) was first proved in Free,...

It was then used in Regular Sequences to prove Ext and Tor versions.

It was proved again in Extensions along with naturalness.

Hom_B(M*N,P)=Hom_A(M,Hom_B(N,P)) was first proved in Extensions in the context of bimodule theory, but (not its naturalness). It will be proved again in Bruns, along with naturalness in bimodule theory.

Edit: naturalness seems to be proved in Extension, not in Bruns.

Hom & Direct, Inverse limits

Kaplansky, Rotman folder