Bockstein spectral sequence

In mathematics, the Bockstein spectral sequence is a spectral sequence relating the homology with mod p coefficients and the homology reduced mod p. It is named after Meyer Bockstein.

Let C be a chain complex of torsion-free abelian groups and p a prime number.

Then we have the exact sequence: Taking integral homology H, we get the exact couple of "doubly graded" abelian groups: where the grading goes:

p ) , deg ⁡ i = ( 1 , − 1 ) , deg ⁡ j = ( 0 , 0 ) , deg ⁡ k = ( − 1 , 0 ) .

This gives the first page of the spectral sequence: we take

with the differential

The derived couple of the above exact couple then gives the second page and so forth.

Explicitly, we have

that fits into the exact couple: where

deg ⁡ (

(the degrees of i, k are the same as before).

Now, taking

of we get: This tells the kernel and cokernel of

Expanding the exact couple into a long exact sequence, we get: for any r, When

, this is the same thing as the universal coefficient theorem for homology.

Assume the abelian group

is finitely generated; in particular, only finitely many cyclic modules of the form

can appear as a direct summand of

free part of

{\displaystyle ({\text{free part of }}H_{*}(C))\otimes \mathbb {Z} /p}

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