On Functional Graphs of Quadratic Polynomials

ABSTRACT

We study functional graphs generated by quadratic polynomials over prime fields. We introduce efficient algorithms for methodical computations and provide the values of various direct and cumulative statistical parameters of interest. These include: the number of connected functional graphs, the number of graphs having a maximal cycle, the number of cycles of fixed size, the number of components of fixed size, as well as the shape of trees extracted from functional graphs. We particularly focus on connected functional graphs, that is, the graphs that contain only one component (and thus only one cycle). Based on the results of our computations, we formulate several conjectures highlighting the similarities and differences between these functional graphs and random mappings.

KEYWORDS:

• Polynomial maps
• functional graphs
• finite fields
• random maps
• algorithms

Mathematics Subject Classification:

• 05C20
• 05C85
• 11T24

Funding

For the research, B.M. was partially supported by the Australian Research Council Grants DP140100118 and DP170102794, M.S. by the Macquarie University Research Fellowship, I.S. by the Australian Research Council Grants DP130100237 and DP140100118.