Göllnitz-Gordon identities and Ramanujan-Göllnitz-Gordon continued fractions
introduction
q-hypergeometric series
- Slater 34
\(\sum_{n=0}^{\infty}\frac{q^{n^2+2n}(-q;q^{2})_{n}}{ (q^{2};q^{2})_{n}}=1/(q^{3};q^{8})_{\infty}(q^{4};q^{8})_{\infty}(q^{5};q^{8})_{\infty}}\) - Slater 36
\(\sum_{n=0}^{\infty}\frac{q^{n^2}(-q;q^{2})_{n}}{ (q^{2};q^{2})_{n}}=1/(q^{1};q^{8})_{\infty}(q^{4};q^{8})_{\infty}(q^{7};q^{8})_{\infty}}\)
- lifting to rank 2 case
Using the Guass formula (in useful techniques in q-series)
\(\prod_{r=0}^{n-1}(1+zq^r)=(1+z)(1+zq)\cdots(1+zq^{n-1})= \sum_{r=0}^{n} \begin{bmatrix} n\\ r\end{bmatrix}_{q}q^{r(r-1)/2}z^r\)
we can rewrite \((-q;q^{2})_{n}\) as
\((-q;q^{2})_{n}=\sum_{r=0}^{n} \begin{bmatrix} n\\ r\end{bmatrix}_{q}q^{r^{2}}\)
Therefore,
\(\sum_{n=0}^{\infty}\frac{q^{n^2}(-q;q^{2})_{n}}{ (q^{2};q^{2})_{n}}=\sum_{n=0}^{\infty}\frac{q^{n^2}\sum_{r=0}^{n} \begin{bmatrix} n\\ r\end{bmatrix}_{q}q^{r^{2}}}{ (q^{2};q^{2})_{n}}\)
\(=\sum_{i,j\geq 0}\frac{q^{(i+j)^2}q^{j^2}}{(-q)_{i+j}(q)_{j}(q)_{i}}=\sum_{i,j\geq 0}\frac{q^{i^2+2ij+2j^2}}{(-q)_{i+j}(q)_{j}(q)_{i}}\)
and
\(\sum_{n=0}^{\infty}\frac{q^{n^2+2n}(-q;q^{2})_{n}}{ (q^{2};q^{2})_{n}}=\sum_{i,j\geq 0}\frac{q^{i^2+2ij+2j^2}q^{2(i+j)}}{(-q)_{i+j}(q)_{j}(q)_{i}}\)
one can obtain the following matrix from the above hypergeometric series\[ \begin{bmatrix} 4 & 2 \\ 2 & 2 \end{bmatrix}\]
history
encyclopedia
- http://en.wikipedia.org/wiki/
- http://www.scholarpedia.org/
- Princeton companion to mathematics(Companion_to_Mathematics.pdf)
articles
- Explicit evaluations of Ramanujan-Göllnitz-Gordon continued fraction
- Nayandeep Deka Baruah and Nipen Saikia, 2008
- Certain identities for Ramanujan–Göllnitz–Gordon continued fraction
- K.R. Vasuki, and B.R. Srivatsa Kumar, 2005
- On the Expansion of a Continued Fraction of Gordon
- Michael D. Hirschhorn, 2001
- On the Ramanujan-G¨ollnitz-Gordon Continued Fraction
- Heng Huat Chan and Sen-Shan Huang, 1997
- Heng Huat Chan and Sen-Shan Huang, 1997
- Partition identities and a continued fraction of Ramanujan
- Krishnaswami Alladi and Basil Gordon, 1993
- Partitionen mit Differenzenbedingungen
- H. Göllnitz, J. Reine Angew. Math. 225 (1967), 154–190.
- H. Göllnitz, J. Reine Angew. Math. 225 (1967), 154–190.
- A Combinatorial Generalization of the Rogers-Ramanujan Identities
- Gordon, B. Amer. J. Math. 83, 393-399, 1961
- Gordon, B. Amer. J. Math. 83, 393-399, 1961