472
OX THE BINOMIAL THEOREM,
[533
where the last letter is repeated; there exists in this case no partition of 8, such
that operating on the last we obtain from it 144, but there does exist a partition
of 8, viz. 134, such that operating on the last but one we obtain from it 144. That
is, for any partition whatever of 9 there exists one (and only one) partition of 8,
such that operating on the last or the last but one, we obtain from it the partition
of 9; that is, taking the entire system of the partitions of 8, and operating on the
last and the last but one, we obtain, and that without repetitions, the entire series
of the partitions of 9; and so in general.
Translating the example into letters, but using for greater convenience a 2 , &c.
instead of a, a, &c. the process
a, b, c, d, e, we have
i will
be
precisely
the
same ;
taking the
letters to be
a 3 orb a 2 c
a 2 d
a 2 e
abe
ace ade
ae 2
be 2
ce 2 de 2 e 3
ab 2
abc
abd
acd
ad 2 bee
bde
ede
d : e
b s
ac 2
b 2 d
b 2 e bd 2
c 2 e
d 3
b 2 c
be 2
bed, c 2 d
cd 2
Attributing weights to the
seven
il letters,
viz. to a,
b, c.
, d, e
the weights
1, 2, 3, 4, 5
respectively, the several columns show the terms of the weights 3, 4, ...15 respectively.
I have said that the foregoing rule is given implicitly in Arbogasts Calculus of
Derivations; this calculus includes in fact a process for the expansion of a function
(fr (a + bx + cx 2 + dx 3 + &c.)
in powers of x; the expansion in question may be obtained by means of Taylor’s
theorem, viz.
(fr (a + bx + cx- + dec 3 4- &c.)
= <fra
+ ip (bx + cx 2 + dx 3 4- &c.)
<b"(l
+ (bx + cx 2 4- dx 3 4- &c.) 2
4- ^ ^2 ^3 CX ~ + ^ c -) 3 >
viz. expanding the several powers of the polynomial increment, and arranging in powers
of x, this is
= cfra
+ x {(fr'a. b)
4- x 2 (^fr'a . c 4- <fr' a .
4- x? ($>'a . d 4- (fr"a . be + (fr'"a. pj
4- x 4 1 (fr'a . e 4- <f>"a. (bd 4- %c 2 ) 4- <f>"'a. ~ 4- (fr""a .