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arXiv math/0506463math.LO
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一个无结构规则的最小经典微积分

A minimal classical sequent calculus free of structural rules

Dominic Hughes

摘要:

Gentzen的经典微积分LK有明确的收缩和弱化的结构规则。它们可以被吸收(在右侧公式中),通过将公理P,(不是P)替换为Gamma,P,(不是P),对于任何上下文Gamma,并将原始析取规则替换为Gamma,A,B意味着Gamma,(A或B)。本文提出了一个经典的公理演算,它也是免费的收缩和削弱,但更对称:收缩和削弱都吸收到合取,保持公理规则完整。它使用混合合取规则,结合了标准的上下文共享和上下文拆分规则:Gamma,Delta,A和Gamma,Sigma,B意味着Gamma,Delta,Sigma,(A和B)。我们将这个系统M称为最小相继式演算。我们证明了一个极小定理的命题片段Mp:任何命题微积分S(在一个标准类的右侧演算)是完整的,当且仅当S包含Mp(即,每一个规则的Mp是可导的S)。因此,我们可以把M看作是根岑的LK的最小的完整核心。

英文摘要:

Gentzen's classical sequent calculus LK has explicit structural rules for contraction and weakening. They can be absorbed (in a right-sided formulation) by replacing the axiom P,(not P) by Gamma,P,(not P) for any context Gamma, and replacing the original disjunction rule with Gamma,A,B implies Gamma,(A or B). This paper presents a classical sequent calculus which is also free of contraction and weakening, but more symmetrically: both contraction and weakening are absorbed into conjunction, leaving the axiom rule intact. It uses a blended conjunction rule, combining the standard context-sharing and context-splitting rules: Gamma,Delta,A and Gamma,Sigma,B implies Gamma,Delta,Sigma,(A and B). We refer to this system M as minimal sequent calculus. We prove a minimality theorem for the propositional fragment Mp: any propositional sequent calculus S (within a standard class of right-sided calculi) is complete if and only if S contains Mp (that is, each rule of Mp is derivable in S). Thus one can view M as a minimal complete core of Gentzen's LK.

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。

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