175
578] A MEMOIR ON THE TRANSFORMATION OF ELLIPTIC FUNCTIONS.
3
Arranging
the results
in a tabular form and
adding the
values of the deficiency,
we have
dps.
dps.
Def.
I.
1 + 12 + 8
= 21, =
15,
II.
1 + 12 + 4 + 12
29,
7,
III.
1 + 12 + 2+ 6 + 12
33,
3,
IV.
1 + 12 + 1 + 3+ 6 + 12
35,
V
so that the curve IV. is a curve of deficiency 1, or bicursal curve. It appears by
Jacobi’s investigation for the quintic transformation (Fund. Nov. pp. 26—28, [Ges. Werke,
t. I., pp. 77—79]) that we can in fact express x, y, that is, u s , v s , rationally in terms
of the parameters a, /3 connected by the equation
a 3 = 2/3 (1 + a + /3),
which is that of a general cubic (deficiency = 1); in fact, we have
that is,
where a, /3 satisfy the relation just referred to. The actual verification of the equation
IV. by means of these values would be a work of some labour.
79. In the general case p an odd prime, then in I. we have at the origin one dp
(in the nature of a fleflecnode) and at infinity two singular points each = ^(p — l)(p — 2) dps.
I infer, from a result obtained by Professor Smith, that there are besides (p — l)(p — 3)
dps; but I have not investigated the nature of these. And the Table of dps and
deficiency then is
I. l+(p-l)(p-2)+ (p— l)(p —3)
II. 1 + (p — 1) (i> — 2) + ^ (p — 1) (p — 3) + £ (p 2 — 1)
III. 1 + (p - 1) (p - 2) + \(p - l)(p- 3) + ±(p 2 - 1) + HP 2 -!)
IV. l+(p —l)(p-2) + £(p —l)(p —3) + £(p 2 — l) + KP 2 —im(P 2 “l)
dps.
Def.
2p 2 —
7p
+ 6,
4p —
5,
2p 2 —
5p
+ 4,
2p —
3,
2p 2 —
4p
+ 3,
p-
2,
2p 2 —
\P
+ f,
hp-
f 5
viz. his values of the deficiencies being as in the last column, the total number of
dps must be as in the last but one column.