Weizmann Logo
ECCC
Electronic Colloquium on Computational Complexity

Under the auspices of the Computational Complexity Foundation (CCF)

Login | Register | Classic Style



REPORTS > KEYWORD > MODULAR FACTORIALS:
Reports tagged with Modular Factorials:
TR26-211 | 25th September 2026
Yann Tal

Computing Modular Factorials Below the Square-Root Barrier

Given a prime $p$, an integer $0\le n\le p-1$, and a divisor $q\mid(1+p+p^2)$, we compute $n!\bmod p$ in expected bit complexity $\widetilde{O}\left(q^c+\frac{\sqrt{p}}{q^{1/4}}\right)$ for some absolute constant $c\ge1$. More generally, the construction applies when $q\mid\Phi_r(p)$, where $\Phi_r$ is the $r$-th cyclotomic polynomial and $r$ is any fixed odd prime power. Combining ... more >>>




ISSN 1433-8092 | Imprint