Abstract
We give a new proof of Ramanujan’s modular identity relating R(q) with R(q 5), where R(q) is the famous Rogers–Ramanujan continued fraction. Our formulation is stronger than those of preceding authors; in particular, we give for the first time identities for the expressions appearing in the numerator and the denominator of Ramanujan’s identity. A related identity for R(q) that has partition-theoretic connections is also proved.
Similar content being viewed by others
References
Andrews, G.E.: Ramanujan’s “lost” notebook III. The Rogers–Ramanujan continued fraction. Adv. Math. 41, 186–208 (1981)
Andrews, G.E., Berndt, B.C.: Ramanujan’s Lost Notebook, Part I. Springer, New York (2005)
Andrews, G.E., Paule, P.: MacMahon’s partition analysis XI: Hexagonal plane partitions. Acta Arith. 126(3), 281–294 (2007)
Andrews, G.E., Berndt, B.C., Jacobsen, L., Lamphere, R.L.: The Continued Fractions Found in the Unorganized Portions of Ramanujan’s Notebooks. Memoir Amer. Math. Soc., vol. 99, No. 477 (1992)
Berndt, B.C.: Ramanujan’s Notebooks III. Springer, New York (1991)
Berndt, B.C.: Ramanujan’s Notebooks V. Springer, New York (1998)
Berndt, B.C., Chan, H.H., Huang, S.-S., Kang, S.-Y., Sohn, J., Son, S.H.: The Rogers–Ramanujan continued fraction. J. Comput. Appl. Math. 105, 9–24 (1999)
Berndt, B.C., Huang, S.-S., Sohn, J., Son, S.H.: Some theorems on the Rogers–Ramanujan continued fraction in Ramanujan’s lost notebook. Trans. Am. Math. Soc. 352, 2157–2177 (2000)
Bowman, D., McLaughlin, J.: On the divergence of the Rogers–Ramanujan continued fraction on the unit circle. Trans. Am. Math. Soc. 356(8), 3325–3347 (2004)
Chan, H.-C., Ebbing, S.: Factorization theorems for the Rogers–Ramanujan continued fraction in the Lost Notebook. Preprint
Gugg, C.: Two modular equations for squares of the Rogers–Ramanujan functions with applications. Ramanujan J. 18(2), 183–207 (2009)
Gugg, C.: Cubes of the Rogers–Ramanujan functions, analogues, and applications (in preparation)
Hirschhorn, M.D.: On the expansion of Ramanujan’s continued fraction. Ramanujan J. 2(4), 521–527 (1998)
Hirschhorn, M.D.: An identity of Ramanujan, and applications. Contemp. Math. 254, 229–234 (2000)
Hirschhorn, M.D., Hunt, D.C.: A simple proof of the Ramanujan conjecture for powers of 5. J. Reine Angew. Math. 326, 1–17 (1981)
Hirschhorn, M.D., Sellers, J.A.: On recent congruence results of Andrews and Paule for broken k-diamond partitions. Bull. Aust. Math. Soc. 75, 121–126 (2007)
Kang, S.-Y.: Some theorems on the Rogers–Ramanujan continued fraction and associated theta functions in Ramanujan’s lost notebook. Ramanujan J. 3, 91–111 (1999)
Kang, S.-Y.: Ramanujan’s formulas for the explicit evaluation of the Rogers–Ramanujan continued fraction and theta-functions. Acta Arith. 90, 49–68 (1999)
Ramanathan, K.G.: On Ramanujan’s continued fraction. Acta Arith. 43, 209–226 (1984)
Ramanathan, K.G.: On the Rogers–Ramanujan continued fraction. Proc. Indian Acad. Sci. (Math. Sci.) 93, 67–77 (1984)
Ramanathan, K.G.: Ramanujan’s continued fraction. Indian J. Pure Appl. Math. 16, 695–724 (1985)
Ramanathan, K.G.: Some applications of Kronecker’s limit formula. J. Indian Math. Soc. 52, 71–89 (1987)
Ramanujan, S.: Some properties of p(n), the number of partitions of n. Proc. Camb. Philos. Soc. XIX, 207–210 (1919)
Ramanujan, S.: Notebooks, 2 vols. Tata Instititute of Fundamental Research, Bombay (1957)
Ramanujan, S.: Collected Papers of Srinivasa Ramanujan. Chelsea, New York (1962). Edited with notes by G.H. Hardy, P.V. Aiyar, and B.M. Wilson
Ramanujan, S.: The Lost Notebook and Other Unpublished Papers. Narosa, New Delhi (1988)
Richmond, B., Szekeres, G.: The Taylor coefficients of certain infinite products. Acta Sci. Math. 40, 347–369 (1978)
Rogers, L.J.: Second memoir on the expansion of certain infinite products. Proc. Lond. Math. Soc. 25, 318–343 (1894)
Rogers, L.J.: On a type of modular relation. Proc. Lond. Math. Soc. 19, 387–397 (1921)
Somos, M.: Private communications, October, 2008
Watson, G.N.: Theorems stated by Ramanujan (VII): Theorems on continued fractions. J. Lond. Math. Soc. 4, 39–48 (1929)
Watson, G.N.: Theorems stated by Ramanujan (IX): Two continued fractions. J. Lond. Math. Soc. 4, 231–237 (1929)
Yi, J.: Modular equations for the Rogers–Ramanujan continued fraction and the Dedekind–eta function. Ramanujan J. 5(4), 377–384 (2001)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Gugg, C. A new proof of Ramanujan’s modular equation relating R(q) with R(q 5). Ramanujan J 20, 163–177 (2009). https://doi.org/10.1007/s11139-009-9180-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11139-009-9180-2
Keywords
- Rogers–Ramanujan continued fraction
- Rogers–Ramanujan functions
- Modular equation
- Ramanujan’s notebooks
- Ramanujan’s lost notebook