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23 Weierstrass Elliptic and Modular FunctionsNotation

§23.1 Special Notation

(For other notation see Notation for the Special Functions.)

\mathbb{L} lattice in \mathbb{C}.
\ell,n integers.
m integer, except in §23.20(ii).
z=x+iy complex variable, except in §§23.20(ii), 23.21(iii).
[a,b] or (a,b) closed, or open, straight-line segment joining a and b, whether or not a and b are real.
primes derivatives with respect to the variable, except where indicated otherwise.
K\left(k\right), K'\left(k\right) complete elliptic integrals (§19.2(i)).
2\omega_{1},2\omega_{3} lattice generators (\Im\left(\omega_{3}/\omega_{1}\right)>0).
\omega_{2} -\omega_{1}-\omega_{3}.
\tau=\omega_{3}/\omega_{1} lattice parameter (\Im\tau>0).
q=e^{i\pi\omega_{3}/\omega_{1}}
\phantom{q}=e^{i\pi\tau} nome.
\Delta discriminant {g_{2}}^{3}-27{g_{3}}^{2}.
n\mathbb{Z} set of all integer multiples of n.
S_{1}/S_{2} set of all elements of S_{1}, modulo elements of S_{2}. Thus two elements of S_{1}/S_{2} are equivalent if they are both in S_{1} and their difference is in S_{2}. (For an example see §20.12(ii).)
G\times H Cartesian product of groups G and H, that is, the set of all pairs of elements (g,h) with group operation (g_{1},h_{1})+(g_{2},h_{2})=(g_{1}+g_{2},h_{1}+h_{2}).

The main functions treated in this chapter are the Weierstrass \wp-function \wp\left(z\right)=\wp\left(z|\mathbb{L}\right)=\wp\left(z;g_{2},g_{3}\right); the Weierstrass zeta function \zeta\left(z\right)=\zeta\left(z|\mathbb{L}\right)=\zeta\left(z;g_{2},g_{3}\right); the Weierstrass sigma function \sigma\left(z\right)=\sigma\left(z|\mathbb{L}\right)=\sigma\left(z;g_{2},g_{3}\right); the elliptic modular function \lambda\left(\tau\right); Klein’s complete invariant J\left(\tau\right); Dedekind’s eta function \eta\left(\tau\right).

Other Notations

Whittaker and Watson (1927) requires only \Im\left(\omega_{3}/\omega_{1}\right)\neq 0, instead of \Im\left(\omega_{3}/\omega_{1}\right)>0. Abramowitz and Stegun (1964, Chapter 18) considers only rectangular and rhombic lattices (§23.5); \omega_{1}, \omega_{3} are replaced by \omega, \omega^{\prime} for the former and by \omega_{2}, \omega^{\prime} for the latter. Silverman and Tate (1992) and Koblitz (1993) replace 2\omega_{1} and 2\omega_{3} by \omega_{1} and \omega_{3}, respectively. Walker (1996) normalizes 2\omega_{1}=1, 2\omega_{3}=\tau, and uses homogeneity (§23.10(iv)). McKean and Moll (1999) replaces 2\omega_{1} and 2\omega_{3} by \omega_{1} and \omega_{2}, respectively.