SSL Minutes

10 April 2001
Boytcho Dontchev Peytchev


Boytcho may need to be reminded about the bringing of beverages for today.

We need T-shirts to be designed. Ideas that were expressed:

In order to talk about things we need a nice way to name them. Among other reasons there's also the reason of having things published.

Worked on the Proper vs. Rigid linkings. Geir suggested that we call the proper linking "sequential". We can represent each of the pairings as lattice paths and it was suggested that we call the proper linking "Short" and the rigid linking "Tall".

The record shows, that prof. Propp will ask John Conway about names for things.

Then there were round robin, ``What have i been up to?''

Kristin was working with Abe on code that counts specific pairings of DPFLs

Boytcho was playing with Baxter Permutations

Joel is working on what was referred to as "reduced DPFLs" or maybe "even DPFLs" which arise when the black vertices are removed from a chessboard colored graph with a DPFL. One question is how much info is lost in the transition from the complete to the reduced DPFL.

Dan has managed to avoid paying attention to his classes with the help of honeycombs.

Jim is trying to extrapolate the number of tilings of a 2xn rectangle (by dominoes, ribbons, whathaveyou) into the realm of negative n.

Geir is looking at the A(n-1) conjecture with both ASMs and DPFLs

Hal's been hacking the domino shuffling thing.

Nick is working on a BP verifier and wants to get to a generator based on that.

Dominic is working on a different (?) BP generator.

At this point it was suggested that we may want to look into things that BARELY FAIL to be BPs and TOADs with very few -1 in the corresponding pair of ASMs. Is there any correlation in the two?

The question was raised if ppl have difficulties accessing the literature. If so Prof. Propp and Michael Lang may be able to facilitate that on a case by case basis as ppl contact him.

It was observed that an Annotated Bibliography would be A Good Thing. Geir was appointed chief maintainer of said Bibliography.

Then we made a List. The List was of Areas Of Interest in the group. Neither five, nor seven are of them, yet there are six as follows:

  1. the A(n-1) Conjecture: Geir, Abe
  2. The Baxter Permutation Conjecture: Boytcho, Dominic, Nick, Hal, Geir
  3. Hexagonal DPFLs: Dan, Boytcho, Rachel, Hal
  4. "even" DPFLs: Joel
  5. Software: Hal, Boytcho
  6. Specific pairings: Kristin, Boytcho, Abe

The subsets of SSL outlined above, should schedule meeting times between themselves to work on the things they find of common interest.

In B107, Michael showed us a couple programs which are on dodgson: vaxrandom and printtiling. These programs can be found in Jim's directory. vaxrandom is a program which allows you to tile virtually any region you tell it to, While printtiling will make a pretty PostScript file out of the plaintext given by vaxrandom

another thing that was mentioned was drawtile.

some net-resources that are of use are:

People who find themselves lacking software that would help them get things done that they want done should contact Michael, who would then relate people's desires to the Coders among us.

have fun