English

On some claims in Ramanujan's `unpublished' manuscript on the partition and tau functions

Number Theory 2007-05-23 v2

Abstract

Towards the end of his life Ramanujan wrote a manuscript on properties of the partition and tau functions, some parts of which remained unpublished until very recently. Nevertheless, this manuscript gave rise to a lot of subsequent work. In it Ramanujan considers congruences for τ(n)\tau(n) modulo some special primes q. He proves for example that τ(n)dnd11(mod691)\tau(n)\equiv \sum_{d|n}d^{11}({\rm mod}691). He defines tn=1t_n=1 if τ(n)\tau(n) is not divisible by q and tn=0t_n=0 otherwise. He then typically writes: "It can be shown by transcendental methods that k=1ntk=C1ndx(logx)δ+O(n(logn)r). \sum_{k=1}^n t_k=C\int_1^n {dx\over (\log x)^{\delta}}+O({n\over (\log n)^r}). where r is any positive number" (after stating some weaker estimates for the above sum). The number δ\delta is a positve rational number depending on q and for the positive number C Ramanujan usually wrote down an Euler product. In this paper it is shown that Ramanujan's claim for every r>1+δr>1+\delta and each of the special primes q is false. Furthermore, we correct a 1928 paper of Geraldine Stanley who claimed to have disproved Ramanujan's claim in case q=5.

Keywords

Cite

@article{arxiv.math/0201265,
  title  = {On some claims in Ramanujan's `unpublished' manuscript on the partition and tau functions},
  author = {Pieter Moree},
  journal= {arXiv preprint arXiv:math/0201265},
  year   = {2007}
}

Comments

14 pages, 1 table. Slightly revised version that will appear in The Ramanujan Journal