A Three-valued Extension of ECWA

ＡＴｈｒｅｅ－ｖａｌｕｅｄＥｘｔｅｎｓｉｏｎｏｆＥＣＷＡ￥ＨｅＪｉａ；ＱｉｕＹｕｈｕｉ（ＤｅｐａｒｔｍｅｎｔｏｆＣｏｍｐｕｔｅｒｓｃｉｅｎｃｅ，ＳｏｕｔｈｗｅｓｔＣｈｉｎａＮｏｒｍａｌＵｎｉｖｅｒｓｉｔｙ，Ｃｈｏｎｇｑｉｎｇ６３０７１５）Ａｂｓｔｒａ...

In this paper, we present a formalization of CWA using a three yalued logic based on the strong definitions of Kleene to a certain degree. We first define three-valued models of first-order theories and then define a three-valued extension of ECWA- ECWA. In order to process the theory more conveniently and effectively, we make strata for the theory, then, on the base of the result of standard dynamic stratification, we iterately use ECWA3 to get the three-valued extension of ECWA (which is the most powerful version of CWA). Through an example, we show that the three-valued CWA is different from the two-valued CWA and the three-valued CWA is strictly more expressive than the two-valued one.