一句话:提出光滑逼近技术,统一证明随机锦标赛等齐次结构上 CSP 的二分类,并刻画局部一致性可解性。
本文研究有限有界齐次结构上一阶归约的约束满足问题(CSP)的复杂度二分类与局部一致性可解性。作者引入“光滑逼近”这一新证明机制,用于获得 CSP 二分类结果并统一已有证明。借助该机制,作者确认了随机锦标赛的一阶归约的 CSP 二分类猜想,并为随机图等齐次图以及有理数序的扩张给出更短的新证明,同时显著简化已有文献结果。除最后一类结构外,还首次刻画了可由局部一致性方法求解的 CSP。评估为纯理论证明,未涉及实验。
We introduce the novel machinery of smooth approximations, and apply it to confirm the CSP dichotomy conjecture for first-order reducts of the random tournament, and to give new short proofs of the conjecture for various homogeneous graphs including the random graph (STOC’11, ICALP’16), and for expansions of the order of the rationals (STOC’08). Apart from obtaining these dichotomy results, we show how our new proof technique allows to unify and significantly simplify the previous results from the literature. For all but the last structure, we moreover characterize for the first time those CSPs which are solvable by local consistency methods, again using the same machinery.