A plane partition,
, of a positive integer
, is a partition of
in which the parts have been arranged in a 2-dimensional array that is
weakly decreasing (nonincreasing) across rows and down columns. Different
configurations are counted as different plane partitions. As an example, there
are six plane partitions of 3:
An equivalent definition is that a plane partition is a finite subset of
with the property that
if
and
, then
must be an element of
. Here
means
,
, and
. It is useful to be able to visualize a plane
partition as a pile of blocks, one block at each lattice point
. For example, Figure 26.12.1 depicts the pile of
blocks that represents the plane partition of 75 given by
(26.12.2).
The number of plane partitions of
is denoted by
, with
. See Table 26.12.1.
| 0 | 1 | 17 | 18334 | 34 | 281 75955 |
|---|---|---|---|---|---|
| 1 | 1 | 18 | 29601 | 35 | 416 91046 |
| 2 | 3 | 19 | 47330 | 36 | 614 84961 |
| 3 | 6 | 20 | 75278 | 37 | 903 79784 |
| 4 | 13 | 21 | 1 18794 | 38 | 1324 41995 |
| 5 | 24 | 22 | 1 86475 | 39 | 1934 87501 |
| 6 | 48 | 23 | 2 90783 | 40 | 2818 46923 |
| 7 | 86 | 24 | 4 51194 | 41 | 4093 83981 |
| 8 | 160 | 25 | 6 96033 | 42 | 5930 01267 |
| 9 | 282 | 26 | 10 68745 | 43 | 8566 67495 |
| 10 | 500 | 27 | 16 32658 | 44 | 12343 63833 |
| 11 | 859 | 28 | 24 83234 | 45 | 17740 79109 |
| 12 | 1479 | 29 | 37 59612 | 46 | 25435 35902 |
| 13 | 2485 | 30 | 56 68963 | 47 | 36379 93036 |
| 14 | 4167 | 31 | 85 12309 | 48 | 51913 04973 |
| 15 | 6879 | 32 | 127 33429 | 49 | 73910 26522 |
| 16 | 11297 | 33 | 189 74973 | 50 | 1 04996 40707 |
We define the
box
as
Then the number of plane partitions in
is
A plane partition is symmetric if
implies that
. The number of symmetric plane partitions in
is
A plane partition is cyclically symmetric if
implies
. The plane partition in Figure 26.12.1 is
an example of a cyclically symmetric plane partition. The number of cyclically
symmetric plane partitions in
is
or equivalently,
A plane partition is totally symmetric if it is both symmetric and
cyclically symmetric. The number of totally symmetric plane partitions in
is
The complement of
is
. A plane partition is
self-complementary if it is equal to its complement. The number of
self-complementary plane partitions in
is
in
it is
in
it is
A plane partition is transpose complement if it is equal to the
reflection through the
-plane of its complement. The number of transpose
complement plane partitions in
is
The number of symmetric self-complementary plane partitions in
is
in
it is
The number of cyclically symmetric transpose complement plane partitions in
is
The number of cyclically symmetric self-complementary plane partitions in
is
The number of totally symmetric self-complementary plane partitions in
is
A strict shifted plane partition is an arrangement of the parts in a partition so that each row is indented one space from the previous row and there is weak decrease across rows and strict decrease down columns. An example is given by:
A descending plane partition is a strict shifted plane partition in
which the number of parts in each row is strictly less than the largest part
in that row and is greater than or equal to the largest part in the next row.
The example of a strict shifted plane partition also satisfies the conditions
of a descending plane partition. The number of descending plane partitions in
is
The notation
denotes the sum over all plane
partitions contained in
, and
denotes the number of elements
in
.
where
is the sum of the squares of the divisors of
.
Addendum: To ten decimal places,