Status: IN
The solution space admits a complete three-tier reduction hierarchy under the elimination principle: mathematical reduction eliminates iteration entirely (O(1) closed-form), raw streaming eliminates preprocessing (O(n) single-pass), and pipeline variants eliminate brute-force pairing (O(n log n) preprocessing + O(n) scan) — each tier eliminates a structural requirement of the tier below.
three tiers (O(1) math → O(n) streaming → O(n log n) pipeline) form a complete hierarchy; elimination governs all three
Depends on (SL): all-solutions-reduce-to-adapted-streaming, mathematical-reduction-is-third-elimination-axis