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1·Any logic which USES the existential quantifier or the universal quantifier is said to be a predicate logic.

任何逻辑使用存在量词或全称量词是说是一个谓词逻辑。

2·Data query for proposition with universal quantifier and data query for implication proposition are two categories of the most practical and difficult data queries.

带有全称量词命题与蕴含命题的数据查询是数据库应用系统中最实用的两类查询，但也是最难的两种数据查询。