## Speaker:

Michael Albert, Department of Computer Science

## Title:

Machines that move things around (again)

## Location:

Owheo 106 - 1:00 pm, Friday 15 May

## Abstract:

One of the seminal events for the study of permutation patterns was Knuth's classification of those permutations of a list which could be produced using only a single stack. I will discuss some recent work in this vein: a general idea called C-machines which explains in a uniform way a number of previously observed correspondences between permutation classes (1), and partial results on the use of two stacks in parallel which are at least sufficient for asymptotic estimates of the number of permutations they can produce (2).

(1) Joint work with Cheyne Homberger, Jay Pantone, Vince Vatter and (independently) Nathaniel Shar

(2) Joint work with Mireille Bousquet-Mélou