Title
The Power of a Propositional Constant.
Abstract
Monomodal logic has exactly two maximally normal logics, which are also the only quasi-normal logics that are Post complete, and they are complete for validity in Kripke frames. Here we show that addition of a propositional constant to monomodal logic allows the construction of continuum many maximally normal logics that are not valid in any Kripke frame, or even in any complete modal algebra. We also construct continuum many quasi-normal Post complete logics that are not normal. The set of extensions of S4.3 is radically altered by the addition of a constant: we use it to construct continuum many such normal extensions of S4.3, and continuum many non-normal ones, none of which have the finite model property. But for logics with weakly transitive frames there are only eight maximally normal ones, of which five extend K4 and three extend S4.
Year
DOI
Venue
2014
10.1007/s10992-012-9256-0
J. Philosophical Logic
Keywords
Field
DocType
humanidades
Kripke structure,T-norm fuzzy logics,Discrete mathematics,Kripke semantics,Normal modal logic,Modal algebra,Modal logic,Monoidal t-norm logic,Mathematics,Intermediate logic
Journal
Volume
Issue
ISSN
43
1
1573-0433
Citations 
PageRank 
References 
1
0.39
12
Authors
2
Name
Order
Citations
PageRank
Robert Goldblatt1464.66
Tomasz Kowalski212424.06