23]
ON THE TRANSFORMATION OF ELLIPTIC FUNCTIONS.
133
and thus fax is an inverse function, the complete functions of which are \ fa, i fa : and
fa, fa are connected with co, v by the equations
O) —— — (0.03 -f- gfa),
fa = 1 (a'co + g'v),
p
a, g, fa, g' being any integers subject to the conditions that a, g' are odd and fa, g
even ; also
ag' — fag = p,
pg' — vfa — Vp,
pg —va= Ip,
l, l' being any integers whatever. In fact, to prove this, we have . only to consider
the general form of a factor in the numerator of fax. Omitting a constant factor,
this is
(1 mo> + nv + 2rd) < ^ ’
and it is to be shown that we can always satisfy the equation
or the equations
ma> + nv + 2 r6 = m fa + fa fa,
pm + 2 vp = vfa & + fa fa,
pn + 2rv — vfag + fag';
and also that to each set of values of m, n, r, there is a unique set of values of
vfa, fa, and vice versa. This is done in the paper referred to. Moreover, with the
suppositions just made as to the numbers cl, g' being odd and fa, g even, it is obvious
that vfa is odd or even, according as m is, and fa according as n is, which shows
that we can likewise satisfy
m + ho)+n-\-%v + 2r6 = vfa + ^ fa + fa + \ v';
and thus the denominator of </>,# is also reducible to the required form.
Now proceeding to the immediate object of this paper, cl, g, fa, g', and consequently
w!, fa are to a certain extent indeterminate. Let A, B, A', B' be a particular set of
values of a, g, fa, g', and 0, P the corresponding values of fa, fa. We have evidently
A, B' odd and A', B even. Also
AB'-A'B= p,
fiB' — vA' = L'p,
fiB — vA — Lp,
0 (A co + B v),
P
U=-(A'a> + B'v).
p y