Abstract
It is proved in this paper that the positive abstraction scheme is consistent with extensionality only if one drops equality out of the language. The theory obtained is then compared with GPK, a well-known set theory based on an extended positive comprehension scheme.
Citation
Roland Hinnion. Thierry Libert. "Positive abstraction and extensionality." J. Symbolic Logic 68 (3) 828 - 836, September 2003. https://doi.org/10.2178/jsl/1058448441
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