let C : Cycle ℤ := (periodicOrbit (fun x => P.eval x) t).map fun x => P.eval x - x
P : ℤ[X]
t : ℤ
ht : t ∈ periodicPts fun x => Polynomial.eval x P
⊢ IsPeriodicPt (fun x => Polynomial.eval x P) 2 t
P : ℤ[X]
t : ℤ
ht : t ∈ periodicPts fun x => Polynomial.eval x P
C : Cycle ℤ := Cycle.map (fun x => Polynomial.eval x P - x) (periodicOrbit (fun x => Polynomial.eval x P) t)
⊢ IsPeriodicPt (fun x => Polynomial.eval x P) 2 t