Content stub — prose, diagrams, and Lean 4 exercises to be written.
This week covers: What changes after two turns of G. Linearisation near fixed points. Gap τ−φ ≈ 0.382 as the remaining distance.
Primary chapter references from book/: chPI-recurrence.html, ch9-phi.html
-- dm³ 101 · Week 13 · Lean 4 Lab -- Operator: G² (2nd Iteration) -- TODO: fill in theorems and exercises -- stub example : True := trivial