Lattice-valued representation of the cut-elimination theorem
Lattice-valued representation of the cut-elimination theorem
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DOI:
10.21099/tkbjm/1496161672
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发表时间:
1991
影响因子:
0.7
通讯作者:
S. Maehara
中科院分区:
文献类型:
--
作者:
S. Maehara
In 1934 G. Gentzen [1] presented the first order classical and intuitionistic predicate calculi $LK$ and $LJ$, and expressed and proved his Hauptsatz or the cut-elimination theorem for them. In 1953 G. Takeuti [11] announced the fact that his fundamental conjecture or the cut-elimination theorem for his $GLC$ implies finitistically the consistency of analysis, where $GLC$ is a simple type theory formulated analogously to $LK$ From that time on he has proved successively but constructively that the fundamental conjecture is true for many subsystems of $GLC$ . In 1967 M. Takahashi [9] gave a general affirmative solution to Takeuti’s fundamental conjecture by means of non-constructive methods (see also [10]). Takahashi’s proof based on a result of K. Sch\"utte [7] and previously W. Tait [8] had proved the cut-elimination theorem for second order predicate logic. In 1971 G. Y. Girard [2], for the intuitionistic $GLC$ , gave a syntactical cutelimination procedure and proved the finiteness of the procedure by use of nonconstructive arguments but by no use of the law of excluded middle. Gentzen [1] says his Hauptsatz had been found originally for the natural intuitionistic calculus $NJ$, that is a first order intuitionistic system of natural deductins given in [1], but he did not discourse in detail. In 1965 D. Prawitz [5] formulated the Hauptsatz or his normal form theorem for $NJ^{2)}$ (and for a classical natural deduction system admitting no disjunctions nor existential quantifications). There are several studies of the normal form theorem for higher order natural deduction systems: Prawitz [6], P. Martin-Lof [3], [4], and so on. In this paper, as our Main Theorem, we shall give a semi-algebraic representation of the cut-elimination theorem. No concrete cut-elimination procedure