被遗忘的东西的幽灵：关于遗忘后大小的研究
The ghosts of forgotten things: A study on size after forgetting
摘要：
遗忘是从逻辑公式中删除变量，同时保留对其他变量的约束。尽管它是一种形式的减少，它并不总是减少的公式的大小，有时可能会增加它。本文讨论了这种增加的含义，并分析了计算特性的现象。给定一个命题Horn公式，一组变量和一个最大允许大小，决定是否可以用该大小表示忘记公式中的变量在$Σ^p_2$中是$D^p$-hard。在$Σ^p_3$中，无限制命题公式的相同问题是$D^p_2$-困难的。
英文摘要：
Forgetting is removing variables from a logical formula while preserving the constraints on the other variables. In spite of being a form of reduction, it does not always decrease the size of the formula and may sometimes increase it. This article discusses the implications of such an increase and analyzes the computational properties of the phenomenon. Given a propositional Horn formula, a set of variables and a maximum allowed size, deciding whether forgetting the variables from the formula can be expressed in that size is $D^p$-hard in $Σ^p_2$. The same problem for unrestricted propositional formulae is $D^p_2$-hard in $Σ^p_3$.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
