Chapter 23: Strict Remainder Descent

The greedy peel decomposes X = T(A, B, C) · D. For the decomposition to be well-founded — and for uniqueness to follow by induction — the remainder D must be strictly less than X. This chapter proves the Strict Remainder Descent Lemma: D < X whenever X ≥ 2. The proof is a direct consequence of the tower atom being at least 2, together with the division structure of τ-Idx.