English

Finite sets containing near-primitive roots

Number Theory 2020-06-30 v1

Abstract

Fix aZa \in \mathbb{Z}, a{0,±1}a\notin \{0,\pm 1\}. A simple argument shows that for each ϵ>0\epsilon > 0, and almost all (asymptotically 100% of) primes pp, the multiplicative order of aa modulo pp exceeds p12ϵp^{\frac12-\epsilon}. It is an open problem to show the same result with 12\frac12 replaced by any larger constant. We show that if a,ba,b are multiplicatively independent, then for almost all primes pp, one of a,b,ab,a2b,ab2a,b,ab, a^2b, ab^2 has order exceeding p12+130p^{\frac{1}{2}+\frac{1}{30}}. The same method allows one to produce, for each ϵ>0\epsilon > 0, explicit finite sets A\mathcal{A} with the property that for almost all primes pp, some element of A\mathcal{A} has order exceeding p1ϵp^{1-\epsilon}. Similar results hold for orders modulo general integers nn rather than primes pp.

Keywords

Cite

@article{arxiv.2006.15200,
  title  = {Finite sets containing near-primitive roots},
  author = {Komal Agrawal and Paul Pollack},
  journal= {arXiv preprint arXiv:2006.15200},
  year   = {2020}
}

Comments

10 pages + references

R2 v1 2026-06-23T16:39:37.923Z