Apple research paper proves Boolean query DAG evaluation is P-Complete

The paper proves evaluating retrieval language L_R over an inverted index is strictly P-Complete, with Document-at-a-Time iterators facing worst-case O(2^|Q|) blowup. Its ComputePN algorithm bounds evaluation time to O(|Q| · |U_active|) using a Positive-Negative dual representation and DAG memoization.