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Feb 23 at 14:43 review Close votes
Feb 28 at 3:02
Feb 18 at 20:22 comment added David E Speyer I believe that I have proved it, using the extremely helpful reference @SamHopkins found. I wrote up the proof on my version of the question.
Feb 17 at 22:53 comment added David E Speyer Allen, did you ever make progress on this? I just asked the same question mathoverflow.net/questions/464368 .
Oct 9, 2022 at 16:46 comment added Allen Knutson Yeah, nonreducedness is important for me. I'm checking out the Guba-Sapir article math.vanderbilt.edu/sapirmv/ftp/pub/diagramgroups/dg.pdf
Oct 9, 2022 at 16:17 comment added Sam Hopkins According to ams.org/journals/tran/2013-365-05/S0002-9947-2012-05719-9/…: "Tits [31] gave explicit generators for [the graph of reduced words's] fundamental group" and [31] is "J.A. Tits, A local approach to buildings. The geometric vein, pp. 519–547, Springer, New York–Berlin, 1981." This only answers your question in a special case but it might be a place to start for a reference.
Oct 9, 2022 at 16:15 comment added Carl-Fredrik Nyberg Brodda You are really considering the braid semigroup $BS_n$, and (more generally, for any semigroup) your graphs are called the Squier complexes of the semigroup. The fundamental group of such a complex is called a diagram group, see e.g. Guba-Sapir.
Oct 9, 2022 at 16:13 comment added Sam Hopkins Unless I'm getting confused about what you're asking, I think this is usually just called the "graph of reduced words" for an element of a Coxeter group (and you don't really need the language of braids to talk about it). EDIT: whoops, of course I am confused, because you are not necessarily considering reduced words. Sorry! I will leave this comment in case anyone makes the same mistake.
Oct 9, 2022 at 15:51 history asked Allen Knutson CC BY-SA 4.0