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22 Jacobian Elliptic FunctionsProperties

§22.9 Cyclic Identities

Contents
  1. §22.9(i) Notation
  2. §22.9(ii) Typical Identities of Rank 2
  3. §22.9(iii) Typical Identities of Rank 3
  4. §22.9(iv) Typical Identities of Rank 4
  5. §22.9(v) Identities of Higher Rank

§22.9(i) Notation

The following notation is a generalization of that of Khare and Sukhatme (2002).

Throughout this subsection m and p are positive integers with 1\leq m\leq p.

In the remainder of this section the rank of an identity is the largest number of elliptic function factors in any term of the identity. The value of p determines the number of points in the identity. The argument z is suppressed in the above notation, as all cyclic identities are independent of z.

§22.9(ii) Typical Identities of Rank 2

In this subsection 1\leq m\leq p and 1\leq n\leq p.

Three Points

With

22.9.7 \kappa=\operatorname{dn}\left(2K\left(k\right)/3,k\right),
22.9.8 s_{1,3}^{(4)}s_{2,3}^{(4)}+s_{2,3}^{(4)}s_{3,3}^{(4)}+s_{3,3}^{(4)}s_{1,3}^{(4%
)}=\frac{\kappa^{2}-1}{k^{2}},
22.9.9 c_{1,3}^{(4)}c_{2,3}^{(4)}+c_{2,3}^{(4)}c_{3,3}^{(4)}+c_{3,3}^{(4)}c_{1,3}^{(4%
)}=-\frac{\kappa(\kappa+2)}{(1+\kappa)^{2}},
22.9.10 d_{1,3}^{(2)}d_{2,3}^{(2)}+d_{2,3}^{(2)}d_{3,3}^{(2)}+d_{3,3}^{(2)}d_{1,3}^{(2%
)}=d_{1,3}^{(4)}d_{2,3}^{(4)}+d_{2,3}^{(4)}d_{3,3}^{(4)}+d_{3,3}^{(4)}d_{1,3}^%
{(4)}=\kappa(\kappa+2).

These identities are cyclic in the sense that each of the indices m,n in the first product of, for example, the form s_{m,p}^{(4)}s_{n,p}^{(4)} are simultaneously permuted in the cyclic order: m\to m+1\to m+2\to\cdots p\to 1\to 2\to\cdots m-1; n\to n+1\to n+2\to\cdots p\to 1\to 2\to\cdots n-1. Many of the identities that follow also have this property.

§22.9(iii) Typical Identities of Rank 3

Two Points

22.9.11 \left(d_{1,2}^{(2)}\right)^{2}d_{2,2}^{(2)}\pm\left(d_{2,2}^{(2)}\right)^{2}d_%
{1,2}^{(2)}=k^{\prime}\left(d_{1,2}^{(2)}\pm d_{2,2}^{(2)}\right),
22.9.12 c_{1,2}^{(2)}s_{1,2}^{(2)}d_{2,2}^{(2)}+c_{2,2}^{(2)}s_{2,2}^{(2)}d_{1,2}^{(2)%
}=0.

Three Points

With \kappa defined as in (22.9.7),

22.9.13 s_{1,3}^{(4)}s_{2,3}^{(4)}s_{3,3}^{(4)}=-\frac{1}{1-\kappa^{2}}\left(s_{1,3}^{%
(4)}+s_{2,3}^{(4)}+s_{3,3}^{(4)}\right),
22.9.14 c_{1,3}^{(4)}c_{2,3}^{(4)}c_{3,3}^{(4)}=\frac{\kappa^{2}}{1-\kappa^{2}}\left(c%
_{1,3}^{(4)}+c_{2,3}^{(4)}+c_{3,3}^{(4)}\right),
22.9.15 d_{1,3}^{(2)}d_{2,3}^{(2)}d_{3,3}^{(2)}=\frac{\kappa^{2}+k^{2}-1}{1-\kappa^{2}%
}\left(d_{1,3}^{(2)}+d_{2,3}^{(2)}+d_{3,3}^{(2)}\right),
22.9.16 s_{1,3}^{(4)}c_{2,3}^{(4)}c_{3,3}^{(4)}+s_{2,3}^{(4)}c_{3,3}^{(4)}c_{1,3}^{(4)%
}+s_{3,3}^{(4)}c_{1,3}^{(4)}c_{2,3}^{(4)}=\frac{\kappa(\kappa+2)}{1-\kappa^{2}%
}\left(s_{1,3}^{(4)}+s_{2,3}^{(4)}+s_{3,3}^{(4)}\right).

Four Points

22.9.17 d_{1,4}^{(2)}d_{2,4}^{(2)}d_{3,4}^{(2)}\pm d_{2,4}^{(2)}d_{3,4}^{(2)}d_{4,4}^{%
(2)}+d_{3,4}^{(2)}d_{4,4}^{(2)}d_{1,4}^{(2)}\pm d_{4,4}^{(2)}d_{1,4}^{(2)}d_{2%
,4}^{(2)}=k^{\prime}{\left(\pm d_{1,4}^{(2)}+d_{2,4}^{(2)}\pm d_{3,4}^{(2)}+d_%
{4,4}^{(2)}\right)},
22.9.18 \left(d_{1,4}^{(2)}\right)^{2}d_{3,4}^{(2)}\pm\left(d_{2,4}^{(2)}\right)^{2}d_%
{4,4}^{(2)}+\left(d_{3,4}^{(2)}\right)^{2}d_{1,4}^{(2)}\pm\left(d_{4,4}^{(2)}%
\right)^{2}d_{2,4}^{(2)}=k^{\prime}{\left(d_{1,4}^{(2)}\pm d_{2,4}^{(2)}+d_{3,%
4}^{(2)}\pm d_{4,4}^{(2)}\right)},
22.9.19 c_{1,4}^{(2)}s_{1,4}^{(2)}d_{3,4}^{(2)}+c_{3,4}^{(2)}s_{3,4}^{(2)}d_{1,4}^{(2)%
}=c_{2,4}^{(2)}s_{2,4}^{(2)}d_{4,4}^{(2)}+c_{4,4}^{(2)}s_{4,4}^{(2)}d_{2,4}^{(%
2)}=0.

§22.9(iv) Typical Identities of Rank 4

Two Points

22.9.20 \left(d_{1,2}^{(2)}\right)^{3}d_{2,2}^{(2)}\pm\left(d_{2,2}^{(2)}\right)^{3}d_%
{1,2}^{(2)}=k^{\prime}\left(\left(d_{1,2}^{(2)}\right)^{2}\pm\left(d_{2,2}^{(2%
)}\right)^{2}\right),
22.9.21 k^{2}c_{1,2}^{(2)}s_{1,2}^{(2)}c_{2,2}^{(2)}s_{2,2}^{(2)}=k^{\prime}\left(1-%
\left(s_{1,2}^{(2)}\right)^{2}-\left(s_{2,2}^{(2)}\right)^{2}\right).

Three Points

Again with \kappa defined as in (22.9.7),

22.9.23 s_{1,3}^{(4)}d_{1,3}^{(4)}c_{2,3}^{(4)}c_{3,3}^{(4)}+s_{2,3}^{(4)}d_{2,3}^{(4)%
}c_{3,3}^{(4)}c_{1,3}^{(4)}+s_{3,3}^{(4)}d_{3,3}^{(4)}c_{1,3}^{(4)}c_{2,3}^{(4%
)}=\frac{\kappa^{2}}{1-\kappa^{2}}\left(s_{1,3}^{(4)}d_{1,3}^{(4)}+s_{2,3}^{(4%
)}d_{2,3}^{(4)}+s_{2,3}^{(4)}d_{2,3}^{(4)}\right).

§22.9(v) Identities of Higher Rank

For extensions of the identities given in §§22.9(ii)22.9(iv), and also to related elliptic functions, see Khare and Sukhatme (2002), Khare et al. (2003).