Expressing Sets With Ultrafilters and the Canonicity of the Sahlqvist Logics
نویسنده
چکیده
This paper will look at Sahlqvist’s theorem in a new way. We introduce and investigate a “skewed” type of semantics for modal logics over their canonical frames. We will use this semantics, to describe every subset of a canonical frame, we will show that the semantics respects all Sahlqvist formulae, and we then conclude that the Sahlqvist logics are canonical. This will be accomplished without refering to any first order properties of the canonical accessibility relation. Expressing Sets With Ultrafilters and the Canonicity of the Sahlqvist Logics Timothy J. Surendonk September 27, 1996
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تاریخ انتشار 1995