MSc. Thesis Defense:Ayşegül Yavuz

MSc. Thesis Defense:Ayşegül Yavuz

 

Ramanujan's Congruences for the Partition Function modulo 5, 7, 11

 

 

 

Ayşegül Yavuz
Mathematics, MSc. Thesis, 2018

 

 

 

Thesis Jury

 

Assoc. Prof. Dr.  Kağan Kurşungöz (Thesis Advisor),  

 

Asst. Prof. Dr Ayesha Asloob Qureshi,      

 

 Asst. Prof. Dr.  Zafeirakis Zafeirakopoulos

 

 

 

 

 

Date & Time: 12th December, 2018 –  13.30 PM

 

Place: Fens 2008

Keywords : Jacobi's triple product identity, integer partition, Ramanujan's congruences, Winquist's identity, q-series

 

 

 

 

 

 

 

Abstract

 

 

 

In 1919, Ramanujan introduced three congruences satisfied by the partition function p(n), namely p(5n+4) ≡ 0 mod 5, p(7n+5) ≡ 0 mod 7 and p(11n+6) ≡ 0 mod 11. In this thesis, our aim is to present different proofs of each of these congruences. For the congruence p(5n+4) ≡ 0 mod 5, we present three types of proofs from elementary to non-elementary. We observe that the elementary proofs of the congruences p(5n+4) and p(7n+5) are analogues with minor variations. The second proof of the congruences p(7n+5) can be regarded as non-elementary proof. Even though their non-elementary proofs are similar to each other, the proof of the congruence in modulo 7 involves considerably more computations on identities, inevitably,  than the proof of the congruence in modulo 5. We further present three worth-stressing proofs for the congruence p(11n+6) ≡ 0 mod 11; The first is proved by Winquist using a representation of  as a double series and a two parameter identity is utilized for this double sum. Then Hirschhorn  proves this congruence  using a four parameter generalization of Winquist's identity and modifies the representation of  . Lastly, owing to Ramanujan, B. Berndt, et al., prove the congruence p(11n+6) ≡ 0 mod 11 directly using a new representation for . We complete the thesis by presenting a more direct and a uniform proof, given by Hirschhorn  in 1994, that can be applicable to all three congruences. This proof is partially based on linear algebra, which makes it reasonably different from Winquist's and Hirschhorn's earlier proofs.