Correlates of War Formal Alliances (v4.1)战争相关因素正式联盟数据（v4.1）

The Correlates of War Formal Alliances dataset records defense, neutrality, non-aggression, and entente commitments from 1816 to 2012. Each row here is one official directed alliance spell between two states, retaining start/end dates, censoring flags, and the terms that apply in that direction. The directed spell product is used because it preserves asymmetric obligations and avoids the documented column shift found in the package's undirected dyad-year rows for the two alliances added in v4.1.

战争相关因素正式联盟数据记录 1816—2012 年的防御、中立、互不侵犯和协商承诺。这里每行是一条官方有向联盟 spell，保留起止日期、删失标记以及该方向适用的条款。选择有向 spell 产品是因为它能保留非对称义务，并避开 v4.1 包中两个新增联盟在无向 dyad-year 文件里的列错位。