Reduced Products, Horn Sentences, and Decision Problems
نویسنده
چکیده
We shall consider a first order language with equality, and the corresponding structures. Reduced products {powers) and Horn sentences are defined in [4, pp. 199, 211]. An Vn sentence is a prenex sentence whose prefix consists of a block of universal quantifiers, followed by a block of existential quantifiers, followed by another block of universal quantifiers, and so on n times; an sentences are defined dually. An EC (HC, VnC) is the class of all models of an elementary sentence (Horn sentence, Vn sentence), and an EC A (HCA, VWCA) is the class of all models of a set of elementary sentences (Horn sentences, Vn sentences).
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تاریخ انتشار 2007