The main distinction between 「subset」 and 「USES」 is that a 「USES」 relationship applies when a use case is a subcase that is also a standalone use case.
「子集」和「使用」之间的主要区别是当用例既是子用例也是独立用例时应用「使用」关系。
The rule of inference used in this procedure is a subcase of linear resolution—the unit resolution.