442
MEMOIR ON THE RESULTANT OF A SYSTEM OF TWO EQUATIONS.
[148
the expression would then become
1 + [1] (1) + [2] (2) + [P] (P) + [21] (21) + [P] (P) + [2 2 ] (2 2 ) + [21 2 ] (2P) + [2 2 1] (2 2 1) + [2 3 ] (2 3 ),
where the terms within the [ ] and ( ) are simply all the partitions of the numbers
1, 2, 3, 4, 5, 6, the greatest part being 2, and the greatest number of parts being 3.
And in like manner in the general case we have all the partitions of the numbers
1, 2, 3,...77171, the greatest part being n, and the greatest number of parts being m.
The symmetric functions (1), (2), (l 2 ), &c. are given in the Tables (b) of the
Memoir on Symmetric Functions, but it is necessary to remark that in the Tables
the first coefficient a is put equal to unity, and consequently that there is a power
of the coefficient a to be restored as a factor: this is at once effected by the con
dition of homogeneity. And it is not by any means necessary to write down (as for
clearness of explanation has been done) the preceding expression for the Resultant;
any portion of it may be taken out directly from one of the Tables (6). For instance,
the bracketed portion
+ pqr (21),
+ q 3 (l 3 ) >
which corresponds to the partitions of the number 3, is to be taken out of the
Table III (b). as follows: a portion of this Table (consisting as it happens of consecutive
lines and columns, but this is not in general the case) is
=
d
be
(21)
+ 3
-1
(I 3 )
-1
if in this we omit the sign =, and in the outside line write for homogeneity ad
instead of d, and in the outside column, first substituting q, p for 1, 2, then write
for homogeneity pqr instead of pq, we have
ad
be
pqr
+ 3
-1
q 3
-1
viz. pqr x (+ 3ad — 16c) + q 3 (— lad), for the value of the portion in question ;
equivalent to
pqr
q 3
ad
+ 3
-1
be
-1
, or as it may be more conveniently written,
this is
in which form it constitutes a part of the expression given in the sequel for the
Resultant of the two functions in question; and similarly the remainder of the expres
sion is at once derived from the Tables (6) I. to VI.