23]
ON THE TRANSFORMATION OF ELLIPTIC FUNCTIONS.
135
We derive from the above the somewhat singular conclusion, that the complete
functions are not absolutely determinate functions of the modulus ; notwithstanding
that they are given by the apparently determinate conditions,
l
dx
— cV) (1 + e 2 x 2 ) ’
l
dx
J (1 + c*x 2 ) (1 — e 2 x?)
In fact definite integrals are in many cases really indeterminate, and acquire
different values according as we consider the variable to pass through real values, or
through imaginary ones. Where the limits are real, it is tacitly supposed that the
variable passes through a succession of real values, and thus a>, v may be considered
as completely determined by these equations, but only in consequence of this tacit
supposition. If c and e are imaginary, there is absolutely no system of values to be
selected for w, v in preference to any other system. The only remaining difficulty is
to show from the integral itself, independently of the theory of elliptic functions, that
such integrals contain an indeterminateness of two arbitrary integers; and this difficulty
is equally great in the simplest cases. Why, d priori, do the functions
contain a single indeterminate integer ?
Obs. I am of course aware, that in treating of the properties of such products as
absolutely necessary to pay attention to the relations between
the infinite limiting values of m and n; and that this introduces certain exponential
factors, to which no allusion has been made. But these factors always disappear from
the quotient of two such products, and to have made mention of them would only
have been embarrassing the demonstration without necessity.