4 papers
Discrete homotopy of token configurations
Bob Lutz
This paper studies graphical analogs of symmetric products and unordered configuration spaces in topology. We do so from the perspective of the discrete homotopy theory introduced…
Higher discrete homotopy groups of graphs
Bob Lutz
This paper studies a discrete homotopy theory for graphs introduced by Barcelo et al. We prove two main results. First we show that if is a graph containing no 3- or 4-cycles,…
Koszulness and supersolvability for Dirichlet arrangements
Bob Lutz
We prove that the cone over a Dirichlet arrangement is supersolvable if and only if its Orlik-Solomon algebra is Koszul. This was previously shown for four other classes of arrange…
Two remarks about nilpotent operators of order two
Stephan Ramon Garcia, Bob Lutz, Dan Timotin
We present two novel results about Hilbert space operators which are nilpotent of order two. First, we prove that such operators are indestructible complex symmetric operators, in…