Hiroakira Ono

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if we formulate our logics in a Gentzen-type formal system. Some syntactical properties of these logics have been studied firstly by the second author in [I I], in connection with the study of BCK-algebras (for information on BCK-algebras, see [9]). There, it turned out that such a syntactical method is a powerful and promising tool in studying(More)
We will give here a purely algebraic proof of the cut elimination theorem for various sequent systems. Our basic idea is to introduce mathematical structures, called Gentzen structures, for a given sequent system without cut, and then to show the completeness of the sequent system without cut with respect to the class of algebras for the sequent system with(More)
In this paper, we will show that the variety of residuated lattices is generated by finite simple residuated lattices. The “simplicity” part of the proof is based on Grǐsin’s idea from [5], whereas the “finiteness” part employs a kind of algebraic filtration argument. Since the set of formulas valid in all residuated lattices is equal to the set of formulas(More)
We develop a general algebraic and proof-theoretic study of substructural logics that may lack associativity, along with other structural rules. Our study extends existing work on (associative) substructural logics over the full Lambek Calculus FL (see e.g. [36, 19, 18]). We present a Gentzen-style sequent system GL that lacks the structural rules of(More)