Beth Definability for the Guarded Fragment
Beth Definability for the Guarded Fragment
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Beth 受保护片段的可定义性
DOI:
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发表时间:
1999
期刊:
影响因子:
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通讯作者:
M. Otto
中科院分区:
文献类型:
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作者:
E. Hoogland;maarten marx;M. Otto
The gueirded fragment (GF) was introduced in [ABN98] as a fragment of first order logic which combines a great expressive power with nice modal behavior. It consists of relationeil first order formulas whose qucintiiiers are relativized by atoms in a certain way. While GF hsis been established as a particularly well-behaved fragment of first order logic in many respects, interpolation fails in restriction to GF, [HM99]. In this paper we consider the Beth property of first order logic and show that, despite the failure of interpolation, it is retained in restriction to GF. Being a closure property w.r.t. definability, the Beth property is of independent interest, both theoretically and for typical potential appUcations of GF, e.g., in the context of description logics. The Beth property for GF is here established on the basis of a limited form of interpolation, which more closely resembles the interpolation property that is usually studied in modal logics. From this we obtain that, more specifically, even every n-variable guarded fragment with up to n-ary relations has the Beth property.