... make use of this fact in the proof of Lemma 4.1.4. Proof of the Main LemmaFor any n ≥ n0, let k be such that csn∈ Im(k)−Im(k+1), and let bnbe an endpoint of Im(k+1)−1. Recall thatAn=|bn|−|csn+1||bn|−|csn|,Bn=|csn||csn+1|/2.The ... inSection 3.1 of [9] (under the name of “tangent extension”) and in Section 12.2 of [13]. We note that these proofs of the starting condition make elaborate use of “complex” methods and do not seem ... well-known, and a proof can be found, for example, in [18].Lemma 2.6. Let τ>0 and 0 <C≤ 1 be constants. Let I be an interval,and let h : I → h(I)=(−τ, 1+τ ) be a diffeomorphism. Assume that forany...