Modelling the Number of Periodic Points of Quadratic Maps Using Random Maps

Sammanfattning: Since the introduction of Pollard's rho method for integer factorisation in 1975 there has been great interest in understanding the dynamics of quadratic maps over finite fields. One avenue for this, and indeed the heuristic on which Pollard bases the proof of the method's efficacy, is the idea that quadratic maps behave roughly like random maps. We explore this heuristic from the perspective of comparing the number of periodic points. We find that empirically random maps appear to model the number of periodic points of quadratic maps well, and moreover prove that the number of periodic points of random maps satisfy an interesting asymptotic behaviour that we have observed experimentally for quadratic maps.