Comments on Some Completeness Theorems of Urquhart and Méndez &; Salto
- Cite this article as:
- Harris, K. & Fitelson, B. Journal of Philosophical Logic (2001) 30: 51. doi:10.1023/A:1017549804474
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Urquhart and Méndez and Salto claim to establish completeness theorems for the system C and two of its negation extensions. In this note, we do the following three things: (1) provide a counterexample to all of these alleged completeness theorems, (2) attempt to diagnose the mistakes in the reported completeness proofs, and (3) provide complete axiomatizations of the desired systems.