Original scientific paper
A note on normal forms for the closed fragment of system IL
Vedran Čačić
orcid.org/0000-0003-2330-9740
; epartment of Mathematics, University of Zagreb, Zagreb, Croatia
Mladen Vuković
Abstract
In [8], P. Hájek and Švejdar determined normal forms for the system ILF, and showed that we can eliminate the modal operator $\rhd$ from $IL$--formulas.
The normal form for the closed fragment of the interpretability logic $IL$ is an open problem (see [13]).
We prove that in some cases we can eliminate the modal operator $\rhd$.
We give an example where it is impossible to eliminate $\rhd.$
Keywords
modal logic; interpretability logic; normal form
Hrčak ID:
82998
URI
Publication date:
12.6.2012.
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