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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≤m≤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≤m≤p and 1≤n≤p.

Three Points

With

22.9.7 κ=dn⁡(2⁢K⁡(k)/3,k),
22.9.8 s1,3(4)⁢s2,3(4)+s2,3(4)⁢s3,3(4)+s3,3(4)⁢s1,3(4)=κ2−1k2,
22.9.9 c1,3(4)⁢c2,3(4)+c2,3(4)⁢c3,3(4)+c3,3(4)⁢c1,3(4)=−κ⁢(κ+2)(1+κ)2,
22.9.10 d1,3(2)⁢d2,3(2)+d2,3(2)⁢d3,3(2)+d3,3(2)⁢d1,3(2)=d1,3(4)⁢d2,3(4)+d2,3(4)⁢d3,3(4)+d3,3(4)⁢d1,3(4)=κ⁢(κ+2).

These identities are cyclic in the sense that each of the indices m,n in the first product of, for example, the form sm,p(4)⁢sn,p(4) are simultaneously permuted in the cyclic order: m→m+1→m+2→⋯⁢p→1→2→⋯⁢m−1; n→n+1→n+2→⋯⁢p→1→2→⋯⁢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 (d1,2(2))2⁢d2,2(2)±(d2,2(2))2⁢d1,2(2)=k′⁢(d1,2(2)±d2,2(2)),
22.9.12 c1,2(2)⁢s1,2(2)⁢d2,2(2)+c2,2(2)⁢s2,2(2)⁢d1,2(2)=0.

Three Points

With κ defined as in (22.9.7),

22.9.13 s1,3(4)⁢s2,3(4)⁢s3,3(4)=−11−κ2⁢(s1,3(4)+s2,3(4)+s3,3(4)),
22.9.14 c1,3(4)⁢c2,3(4)⁢c3,3(4)=κ21−κ2⁢(c1,3(4)+c2,3(4)+c3,3(4)),
22.9.15 d1,3(2)⁢d2,3(2)⁢d3,3(2)=κ2+k2−11−κ2⁢(d1,3(2)+d2,3(2)+d3,3(2)),
22.9.16 s1,3(4)⁢c2,3(4)⁢c3,3(4)+s2,3(4)⁢c3,3(4)⁢c1,3(4)+s3,3(4)⁢c1,3(4)⁢c2,3(4)=κ⁢(κ+2)1−κ2⁢(s1,3(4)+s2,3(4)+s3,3(4)).

Four Points

22.9.17 d1,4(2)⁢d2,4(2)⁢d3,4(2)±d2,4(2)⁢d3,4(2)⁢d4,4(2)+d3,4(2)⁢d4,4(2)⁢d1,4(2)±d4,4(2)⁢d1,4(2)⁢d2,4(2)=k′⁢(±d1,4(2)+d2,4(2)±d3,4(2)+d4,4(2)),
22.9.18 (d1,4(2))2⁢d3,4(2)±(d2,4(2))2⁢d4,4(2)+(d3,4(2))2⁢d1,4(2)±(d4,4(2))2⁢d2,4(2)=k′⁢(d1,4(2)±d2,4(2)+d3,4(2)±d4,4(2)),
22.9.19 c1,4(2)⁢s1,4(2)⁢d3,4(2)+c3,4(2)⁢s3,4(2)⁢d1,4(2)=c2,4(2)⁢s2,4(2)⁢d4,4(2)+c4,4(2)⁢s4,4(2)⁢d2,4(2)=0.

§22.9(iv) Typical Identities of Rank 4

Two Points

22.9.20 (d1,2(2))3⁢d2,2(2)±(d2,2(2))3⁢d1,2(2)=k′⁢((d1,2(2))2±(d2,2(2))2),
22.9.21 k2⁢c1,2(2)⁢s1,2(2)⁢c2,2(2)⁢s2,2(2)=k′⁢(1−(s1,2(2))2−(s2,2(2))2).

Three Points

Again with κ defined as in (22.9.7),

22.9.22 s1,3(2)⁢c1,3(2)⁢d2,3(2)⁢d3,3(2)+s2,3(2)⁢c2,3(2)⁢d3,3(2)⁢d1,3(2)+s3,3(2)⁢c3,3(2)⁢d1,3(2)⁢d2,3(2)=κ2+k2−11−κ2⁢(s1,3(2)⁢c1,3(2)+s2,3(2)⁢c2,3(2)+s3,3(2)⁢c3,3(2)),
22.9.23 s1,3(4)⁢d1,3(4)⁢c2,3(4)⁢c3,3(4)+s2,3(4)⁢d2,3(4)⁢c3,3(4)⁢c1,3(4)+s3,3(4)⁢d3,3(4)⁢c1,3(4)⁢c2,3(4)=κ21−κ2⁢(s1,3(4)⁢d1,3(4)+s2,3(4)⁢d2,3(4)+s2,3(4)⁢d2,3(4)).

§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).