Dear sage-devel, dear group theorists, at ticket #6750, I propose an upgrade of our optional spkg that can compute modular cohomology rings of finite p-groups, ready for review.
As a new feature, the package provides Massey products. This is a structure on cohomology rings that goes beyond the ring structure (it may distinguish isomorphic cohomology rings). By work of D. Kraines, the Massey products are related with the Steenrod powers and the Bockstein operation. For example, on degree one cocycles, the p-fold restricted Massey product is the same as minus the Bockstein operation (compare also the PhD thesis of Borge). The package can compute those things, but the problem is: I can't! That's to say, may knowledge of Bockstein operation, Steenrod powers and Massey products is too basic, I couldn't verify whether my code produces correct (or at least: plausible) results. Hence, I would appreciate if the group theorists among you could verify the doc tests, or could even contribute some further interesting non-trivial examples. One question to William: The repository of cohomology rings is still in my home directory on sage.math. Is there a more appropriate "official" location? Since I added further rings to the repository (e.g., the cohomology ring of the Sylow 2-subgroup of the third Conway group, which is of order 1024), the repository comprises 31Gb of data. Best regards, Simon --~--~---------~--~----~------------~-------~--~----~ To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
