17 research outputs found
Plane overpartitions and cylindric partitions
Generating functions for plane overpartitions are obtained using various
methods such as nonintersecting paths, RSK type algorithms and symmetric
functions. We extend some of the generating functions to cylindric partitions.
Also, we show that plane overpartitions correspond to certain domino tilings
and we give some basic properties of this correspondence.Comment: 42 pages, 11 figures, corrected typos, revised parts, figures
redrawn, results unchange
From Aztec diamonds to pyramids: steep tilings
We introduce a family of domino tilings that includes tilings of the Aztec
diamond and pyramid partitions as special cases. These tilings live in a strip
of of the form for some integer , and are parametrized by a binary word that
encodes some periodicity conditions at infinity. Aztec diamond and pyramid
partitions correspond respectively to and to the limit case
. For each word and for different types of boundary
conditions, we obtain a nice product formula for the generating function of the
associated tilings with respect to the number of flips, that admits a natural
multivariate generalization. The main tools are a bijective correspondence with
sequences of interlaced partitions and the vertex operator formalism (which we
slightly extend in order to handle Littlewood-type identities). In
probabilistic terms our tilings map to Schur processes of different types
(standard, Pfaffian and periodic). We also introduce a more general model that
interpolates between domino tilings and plane partitions.Comment: 36 pages, 22 figures (v3: final accepted version with new Figure 6,
new improved proof of Proposition 11
Perfect sampling algorithm for Schur processes
We describe random generation algorithms for a large class of random
combinatorial objects called Schur processes, which are sequences of random
(integer) partitions subject to certain interlacing conditions. This class
contains several fundamental combinatorial objects as special cases, such as
plane partitions, tilings of Aztec diamonds, pyramid partitions and more
generally steep domino tilings of the plane. Our algorithm, which is of
polynomial complexity, is both exact (i.e. the output follows exactly the
target probability law, which is either Boltzmann or uniform in our case), and
entropy optimal (i.e. it reads a minimal number of random bits as an input).
The algorithm encompasses previous growth procedures for special Schur
processes related to the primal and dual RSK algorithm, as well as the famous
domino shuffling algorithm for domino tilings of the Aztec diamond. It can be
easily adapted to deal with symmetric Schur processes and general Schur
processes involving infinitely many parameters. It is more concrete and easier
to implement than Borodin's algorithm, and it is entropy optimal.
At a technical level, it relies on unified bijective proofs of the different
types of Cauchy and Littlewood identities for Schur functions, and on an
adaptation of Fomin's growth diagram description of the RSK algorithm to that
setting. Simulations performed with this algorithm suggest interesting limit
shape phenomena for the corresponding tiling models, some of which are new.Comment: 26 pages, 19 figures (v3: final version, corrected a few misprints
present in v2
Enumeration of Cylindric Plane Partitions - part I
Cylindric plane partitions may be thought of as a natural generalization of
reverse plane partitions. A generating series for the enumeration of cylindric
plane partitions was recently given by Borodin. The first result of this paper
is a -analog of Borodin's identity which extends previous work by Okada
in the reverse plane partition case. Our proof uses commutation relations for
-vertex operators acting on Macdonald polynomials as given by Garsia,
Haiman and Tesla. The second result of this paper is an explicit combinatorial
interpreation of the -Macdonald weight in terms of a non-intersecting
lattice path model on the cylinder
The free boundary Schur process and applications I
We investigate the free boundary Schur process, a variant of the Schur process introduced by Okounkov and Reshetikhin, where we allow the first and the last partitions to be arbitrary (instead of empty in the original setting). The pfaffian Schur process, previously studied by several authors, is recovered when just one of the boundary partitions is left free. We compute the correlation functions of the process in all generality via the free fermion formalism, which we extend with the thorough treatment of âfree boundary states.â For the case of one free boundary, our approach yields a new proof that the process is pfaffian. For the case of two free boundaries, we find that the process is not pfaffian, but a closely related process is. We also study three different applications of the Schur process with one free boundary: fluctuations of symmetrized last passage percolation models, limit shapes and processes for symmetric plane partitions and for plane overpartitions
A Decomposition of Cylindric Partitions and Cylindric Partitions into Distinct Parts
We show that cylindric partitions are in one-to-one correspondence with a
pair which has an ordinary partition and a colored partition into distinct
parts. Then, we show the general form of the generating function for cylindric
partitions into distinct parts and give some examples. We prove part of a
conjecture by Corteel, Dousse, and Uncu. The approaches and proofs are
elementary and combinatorial.Comment: Second version. Many inaccuracies are corrected thanks to Ole
Warnaar. 44 pages, 50+ figure