POPSTACKS

This package accompanies "The enumeration of permutations sortable by pop stacks in parallel", by myself and Rebecca Smith. It allows one to compute the generating function for the number of permutations that can be sorted by k pop stacks in parallel.

Download the package:

plain text Maple source (version of July 28, 2008)

Example:

First, download the package. Then run Maple, and load the package by typing

> read POPSTACKS;

Maple should respond with something to the effect of

Warning, the protected names norm and trace have been redefined and unprotected

POPSTACKS: A Maple package to compute the generating function for
permutations that can be sorted by k pop stacks in parallel.
Written by Vince Vatter
This version: July 28, 2008
Main procedure: popstacks(k)

Now suppose that you want to count the permutations sortable by three pop stacks in parallel. At the prompt type

> popstacks(3);

Maple will reply

                             2        3        4       5       6
              1 - 13 x + 63 x  - 148 x  + 177 x  - 98 x  + 18 x
              ---------------------------------------------------
                             2        3        4        5       6
              1 - 14 x + 75 x  - 201 x  + 288 x  - 216 x  + 72 x

To get the transition matrix instead, call popstackstm().