Fixed Points and Two-Cycles of the Discrete Logarithm
We explore some questions related to one of Brizolis: does every prime p have a pair (g,h) such that h is a fixed point for the discrete logarithm with base g? We extend this question to ask about not only fixed points but also two-cycles. Campbell and Pomerance have not only answered the fixed point question for sufficiently large p but have also rigorously estimated the number of such pairs given certain conditions on g and h. We attempt to give heuristics for similar estimates given other conditions on g and h and also in the case of two-cycles. These heuristics are well-supported by the data we have collected, and seem suitable for conversion into rigorous estimates in the future.
External Access URL
Holden, Joshua. Fixed points and two-cycles of the discrete logarithm. In: Algorithmic number theory: 5th international symposium; proceedings, no. 2369 in Springer Lecture Notes in Computer Science, Springer-Verlag, 2002.