This system has 8 distinct proper affirmative modalities (plus the improper modality p) and is in neither K2 nor S5 [Pledger, 1972, p270-271]
The distinct affirmative modalities of the syatem are:
p implied by Lp it implies Mp Lp implied by LLp it implies p, LMp, MLp, LMMp Mp it implies MMp implied by p, MLp, LMp, MLLp LLp it implies Lp, LMp, MLLp MMp implied by Mp, MLp, LMMp LMp implied by Lp, LLp it implies Mp, LMMp MLp it implies Mp, MMp implied by Lp, MLLp LMMp implied by Lp, LMp it implies MMp MLLp it implies Mp, MLp implied by LLp
The system 8p is: the system S3 plus one of the following sets:
{ LLMp => p, LMLp => p } or the dual
{ p => MMLp, P => MLMp }
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This page was last modified on November 21st, 2004