Asymptotic Formula for Multipartitions
Let $p_t(N)$ denote the number of $t$-multipartitions of a positive integer $N$. In this article, we obtain an asymptotic formula for $p_t(N)$, when $t \ll N^{1 - \epsilon}$, for any $\epsilon > 0$.
arXiv subjects
Publications and source records attributed to Jayanta Barman.
Let $p_t(N)$ denote the number of $t$-multipartitions of a positive integer $N$. In this article, we obtain an asymptotic formula for $p_t(N)$, when $t \ll N^{1 - \epsilon}$, for any $\epsilon > 0$.
A partition is $t$-regular if none of its parts is divisible by $t$. Let $p(N,t)$ be the number of $(t+1)$-regular partitions of a positive integer $N$. In 1971, Hagis proved an asymptotic formula for $p(N,t)$ using the circle method, when $t$ fixed. In this article, we use the saddle point method and extend the result of Hagis in different ranges of $t$, obtaining explicit bounds. We also discuss an application of our result to estimate zeros in the character table of the symmetric group.
For any two partitions $\lambda$ and $\mu$ of a positive integer $N$, let $\chi_{\lambda}(\mu)$ be the value of the irreducible character of the symmetric group $S_{N}$ associated with $\lambda$, evaluated at the conjugacy class of elements whose cycle type is determined by $\mu$. Let $Z(N)$ be the number of zeros in the character table of $S_N$, and $Z_{t}(N)$ be defined as $$ Z_{t}(N):= \#\{(\lambda,\mu): \chi_{\lambda}(\mu) = 0 \; \text{with $\lambda$ a $t$-core}\}. $$ We prove $$ Z(N) \ge \frac{2\, p(N)^{2}}{\log N} \left(1+O\left(\frac{1}{\sqrt{\log N}}\right)\right), $$ where $p(N)$ denotes the number of partitions of $N$. We also give explicit lower bounds for $Z_t(N)$ in various ranges of $t$.