Further Examples: KleinInvariantJ
The Klein invariant J is an invariant of elliptic curves, equal to , where are the Weierstrass coefficients. The function KleinInvariantJ takes as its argument the ratio between half-periods of the curve, rather than the Weierstrass coefficients.
Two ratios and yield the same J if and only if , for some integers with . Values of thus related can be regarded as coming from different possible pairs of periods for the same elliptic curve (that is, different fundamental parallelograms).
These numbers are integers.