2024/03/07 by Sadek, Mohammad, Wafik, Mohamed, Yesin, Tuğba
#FOS: Mathematics #Number Theory (math.NT)
paper · doi:10.48550/arxiv.2403.04397
Let f be a polynomial with integer coefficients whose degree is at least 2. We consider the problem of covering the orbit Orbf(t)=\t,f(t),f(f(t)),⋯\, where t is an integer, using arithmetic progressions each of which contains t. Fixing an integer k≥ 2, we prove that it is impossible to cover Orbf(t) using k such arithmetic progressions unless Orbf(t) is contained in one of these progressions. In fact, we show that the relative density of terms covered by k such arithmetic progressions in Orbf(t) is uniformly bounded from above by a bound that depends solely on k. In addition, the latter relative density can be made as close as desired to 1 by an appropriate choice of k arithmetic progressions containing t if k is allowed to be large enough.