TopComb seminar, April 21
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Anton Dochtermann
Apr 20, 2011, 6:20:11 PM4/20/11
to Topological Combinatorics
Dear all,
The topological combinatorics seminar will meet tomorrow, returning to
our theme of combinatorial Grassmannians. A couple weeks ago Matthew
showed us how to obtain a matroid bundle from a vector bundle. I will
breifly recall that construction but focus mostly on the 'other
direction', namely how to naturally construct a spherical
quasifibration from a given matroid bundle. The composition of these
transformations induces a splitting in cohomology, and in particular
shows that the cohomology of the rank k MacPhersonian contains a
polynomial ring on the first k Stiefel-Whitney classes (sorting out
the details of that last statement could be the topic of a future
talk). I will mostly follow the Anderson and Davis paper 'Mod 2
cohomology of combinatorial Grassmannians', available on the website.
http://math.stanford.edu/~anton/seminar2011.html
As always we meet at 10AM in Evans 939.
See you tomorrow!
anton
The topological combinatorics seminar will meet tomorrow, returning to
our theme of combinatorial Grassmannians. A couple weeks ago Matthew
showed us how to obtain a matroid bundle from a vector bundle. I will
breifly recall that construction but focus mostly on the 'other
direction', namely how to naturally construct a spherical
quasifibration from a given matroid bundle. The composition of these
transformations induces a splitting in cohomology, and in particular
shows that the cohomology of the rank k MacPhersonian contains a
polynomial ring on the first k Stiefel-Whitney classes (sorting out
the details of that last statement could be the topic of a future
talk). I will mostly follow the Anderson and Davis paper 'Mod 2
cohomology of combinatorial Grassmannians', available on the website.
http://math.stanford.edu/~anton/seminar2011.html
As always we meet at 10AM in Evans 939.
See you tomorrow!
anton
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