SSL Minutes for Thursday, Nov. 6, 2003 Note-taker: Paul Snacks: Abby Note taker for Tuesday: Martin Snacks for Tuesday: Sam Hal: It's Grunt. Jim: I want to meet you all individually on Tuesday. (Assigns times for the meetings) Jim: Instead of attatching documents to emails to ssl, just put a link in an email to the place on your website where we can find it. Paul: Geocities will not allow for .mws uploads Jim, Hal and Jon talk about asking Yvonne to allow our accounts the ability to create webpages through undergrad.math.wisc.edu. Jim: One of the top level goals in SSL is to understand Somos and Somos-like sequences and what they might have to do with combinatorial objects. We want to answer questions like: Can "cube snakes" or appolonian gaskets illuminate anything about Somos or Somos-like sequences? Enter Scott Scheffield. Jim: If anyone doesnt have graph.tcl, they should get it, as it makes large graphs not so tedious. Lets go around and see what everyone has been doing since Tuesday. Hal: I haven't done much in terms of SSL since Tuesday. Carl: Played with the bijection between even 2 x 2 x n perfect matchings and ordered pairs of 3 x 2n domino tilings. Also, looked further into "face matchings". Stephen: Looking at small examples of cluster algebras. Jim: For an example of what we should look for in SSL, double wiring schemes give Laurent polynomials where every coefficient is + or - 1. Could we describe what type of monomials occur? Stephen: Only one dimensional cluster algebra that I know of is the universal degree 2 with the real line and points that are integers. Abby: Read Carls face matching text and Pauls generating function text. Independently reproduced it for odd number of cubes. Jon: Talked with Carl and Paul after the last meeting about odd cubes and 3 x 2n bijection. Emilie: Looking at equations of rational solutions to Jims question about polygonal diagonals and getting somwhere until the variable of interest disappeared. Jim: I'll talk to M. Isaacs about it. Martin: Trying to read a book on automata, but very algebraic and I dont know if I can get through it. Jim: We should take a look at the odd cube polynomials and see if their square roots follow a linear recurrence. Suppose we have a sequence a(1), a(2), a(3), a(4), a(5), a(6)... Then the matrix (a(1) a(2) a(3)) (a(2) a(3) a(4)) (a(3) a(4) a(5)) has a nonzero determinant only if it does not follow a second order linear recurrence, since if it nonsingular it has no nontrivial solutions of (a(1) a(2) a(3)) ( A ) (0) (a(2) a(3) a(4)) ( B ) = (0) (a(3) a(4) a(5)) (-1 ) (0). Lets take a break to eat. (Move to B107, and everyone uses Maple to look at different things) End Meeting.