English

The polynomials $X^2+(Y^2+1)^2$ and $X^{2} + (Y^3+Z^3)^2$ also capture their primes

Number Theory 2023-07-24 v3

Abstract

We show that there are infinitely many primes of the form X2+(Y2+1)2X^2+(Y^2+1)^2 and X2+(Y3+Z3)2X^2+(Y^3+Z^3)^2. This extends the work of Friedlander and Iwaniec showing that there are infinitely many primes of the form X2+Y4X^2+Y^4. More precisely, Friedlander and Iwaniec obtained an asymptotic formula for the number of primes of this form. For the sequences X2+(Y2+1)2X^2+(Y^2+1)^2 and X2+(Y3+Z3)2X^2+(Y^3+Z^3)^2 we establish Type II information that is too narrow for an aysmptotic formula, but we can use Harman's sieve method to produce a lower bound of the correct order of magnitude for primes of form X2+(Y2+1)2X^2+(Y^2+1)^2 and X2+(Y3+Z3)2X^2+(Y^3+Z^3)^2. Estimating the Type II sums is reduced to a counting problem which is solved by using the Weil bound, where the arithmetic input is quite different from the work of Friedlander and Iwaniec for X2+Y4X^2+Y^4. We also show that there are infinitely many primes p=X2+Y2p=X^2+Y^2 where YY is represented by an incomplete norm form of degree kk with k1k-1 variables. For this we require a Deligne-type bound for correlations of hyper-Kloosterman sums.

Keywords

Cite

@article{arxiv.2112.03617,
  title  = {The polynomials $X^2+(Y^2+1)^2$ and $X^{2} + (Y^3+Z^3)^2$ also capture their primes},
  author = {Jori Merikoski},
  journal= {arXiv preprint arXiv:2112.03617},
  year   = {2023}
}

Comments

v3: Corrections to some parts of the proofs v2: Added Theorem 3 on primes p=a^2+N(b_1,...,b_{k-1})^2, where N is an incomplete norm form od degree k, small corrections elsewhere