418 A MEMOIR ON THE SYMMETRIC FUNCTIONS [147
where as usual the summation extends only to the distinct terms, so that e.g. (p 2 )
contains only half as many terms as (pq), and so in all similar cases, then we have
-b = (l), + c = (l 2 ), — d = (l 3 ), &c. ;
and the two problems which arise are, first to express any combination №&... in terms
of the symmetric functions (l x m y ...), and secondly, or conversely, to express any
symmetric function (l x m y ...) in terms of the combinations №c q ... .
It will conduce materially to brevity if 1*22... be termed the partition belonging
to the combination b p c q ... ; and in like manner if l x ni y ... be termed the partition
belonging to the symmetric function (l x m y ...), and if the sum of the component
numbers of the partition is termed the weight.
Consider now a line of combinations corresponding to a given weight, e.g. the
weight 4, this will be
e bd c 2 b-c i 4 (line)
4 13 2 2 1 2 2 T,
where I have written under each combination the partition which belongs to it, and
in like manner a column of symmetric functions of the same weight, viz.
(4) (column)
(31)
(2 2 )
(2P)
(l 4 ),
where, as the partitions are obtained by simply omitting the ( ), I have not separately
written down the partitions.
It is at once obvious that the different combinations of the line will be made up
of numerical multiples of the symmetric functions of the column ; and conversely, that
the symmetric functions of the column will be made up of numerical multiples of the
combinations of the line ; but this requires a further examination. There are certain
restrictions as to the symmetric functions which enter into the expression of the com
bination, and conversely, as to the combinations which enter into the expression of the
symmetric function. The nature of the first restriction is most clearly seen by the
following Table:
Number of
Parts.
Greatest
Part.
Combinations
with their several
Partitions.
Contain Multiples of the
Symmetric Functions.
Greatest Part
does not exceed
Number of
Parts not
less than
1
4
e 4
(I 4 ),
1
4
2
3
bd 13
(l 4 ), (21 2 ),
2
3
2
2
c 2 2 2
(l 4 ), (21 2 ), (2 2 ),
2
2
3
2
b 2 c 1 2 2
(lfi, (21 2 ), (2 2 ), (31),
3
2
4
1
Z> 4 l 4
(l 4 ), (21 2 ), (2 2 ), (31), (4)
4
1