2025/08/22 by Kintu, Brian
#Dynamical Systems (math.DS) #FOS: Mathematics #Number Theory (math.NT)
paper · doi:10.48550/arxiv.2508.16393
In this follow-up paper, we again inspect a surprising relationship between the set of 2-periodic points of a polynomial map φd, c defined by φd, c(z) = zd + c for all c, z ∈ OK and the coefficient c, where K is any number field of degree n≥ 2 and d>2 is an integer. As before, we again study here counting problems that are inspired by the exciting advances on 2-torsion point-counting in arithmetic statistics and on 2-periodic point-counting in arithmetic dynamics. In doing so, we then first prove that for any given prime p≥ 3 and any integer ℓ ≥ 1, the average number of distinct 2-periodic integral points of any φpℓ, c modulo prime ideal pOK is bounded (if ℓ ∈ ℤ+∖ \1,p\) or zero or unbounded (if ℓ ∈ \1,p\) as c tends to infinity. Motivated further by K-rational periodic point-counting work of Benedetto, along with a conjecture of Hutz on 2-periodic rational points of any φ(p-1)ℓ, c for any given prime p≥ 5 and any integer ℓ ≥ 1 in arithmetic dynamics, we then also prove that the average number of distinct 2-periodic integral points of any φ(p-1)ℓ, c modulo prime ideal pOK is 1 or 2 or 0 as c tends to infinity. Finally, we then also apply here density and number field-counting results from arithmetic statistics, and as a result obtain again counting and statistical results on the irreducible monic integer polynomials and algebraic number fields arising naturally in our dynamical setting.