Hofstadter's problem for curious readers

This document summarizes the proofs made during a Coq development inSummer 2015. This development investigates the function G introducedby Hofstadter in his famous “G{"o}del, Escher, Bach” bookas well as a related infinite tree. The left/right flipped variantof this G tree has also been studied here, followingHofstadter’s “problem for the curious reader”.The initial G function is refered as sequence A005206 inOEIS, while the flipped version is the sequence A123070.