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.
Definition
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: and the same for
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 and (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 . Letting we thus see is isomorphic to .
References
- {{Citation | last1=McCleary | first1=John | title=A User's Guide to Spectral Sequences | publisher=Cambridge University Press | edition=2nd | series=Cambridge Studies in Advanced Mathematics | isbn=978-0-521-56759-6 | mr=1793722 | year=2001 | volume=58}}
- J. P. May, [http://www.math.uchicago.edu/~may/MISC/SpecSeqPrimer.pdf A primer on spectral sequences]
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