[Binghamton Geometry/Topology Seminar] Topology/Geometry Seminar this Tuesday (joint with Algebra seminar)
Tam Nguyen Phan
tam at math.binghamton.edu
Sun Oct 11 21:35:02 EDT 2015
BINGHAMTON GEOMETRY/TOPOLOGY SEMINAR (joint with Algebra seminar)
Date: Tuesday, October 13th, 2015
Time: 2.50 pm
Place: Whitney Hall, Room 100E, followed by coffee/tea in the
Hilton Reading Room. Note the new location of the math department (
http://www2. <http://www2.math.binghamton.edu/p/directions>
math.binghamton.edu <http://www2.math.binghamton.edu/p/directions>
/p/directions <http://www2.math.binghamton.edu/p/directions>).
Speaker: *Robert Bieri* (Binghamton University)
Title: *Groups of piecewise isometric permutations of lattice points*
Abstract: An orthant (of the orthogonal integral lattice) is the image
of the standard orthant under an affine-orthogonal transformation. And a
permutation of a subset is piecewise-Euclidean-isometric (pei), if is
a disjoint union of finitely many orthants, , on each of which restricts
to an isometric embedding . I will talk about the group of all
pei-permutations of various subsets and its subgroup of all
piecewise-Eucliden-translation permutations. In the case when consists of
the lattice points on the union of positive coordinate axes then is the
Houghton group .
This is joint work with Heike Sach: we prove finiteness properties of some
pei- and pet- groups, and have, as a consequence, that admits a
K(G,1)-complex with finite -skeleton.
An interesting point is that prominent groups like Richard Thompson's
group crop
up when we extend the consideration to the -lattice in the hyperbolic plane.
NOTE: The seminar has a webpage where the semester's program is listed:
http://www2.math.binghamton.edu/p/seminars/topsem
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www1.math.binghamton.edu/pipermail/topsem/attachments/20151011/61aa1e14/attachment.html>
More information about the topsem
mailing list