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Yves Moinard
Forgetting literals with varying propositional symbols
, Common Sense 2005 (7th Int. Symp. on Logical Formalization of Common Sense Reasoning)
, Technische Universitat Dresden
, Corfu, Greece
, 169-176
, may
, 2005
, Document
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Abstract
Recently, the old logical notion of forgetting propositional symbols (or
reducing the logical vocabulary) has been generalized to a new notion:
forgetting literals. The aim was to help the automatic computation of various
formalisms which are currently used in knowledge representation.
We extend here this notion, by allowing propositional symbols to vary
while forgetting literals. The definitions are not really more complex than
for literal forgetting without variation.
We describe the new notion, on the syntactical and the semantical side.
Then, we show how to apply it to the computation of circumscription.
This computation has been done before with standard literal forgetting,
but here
we show how introducing varying propositional symbols
simplifies significantly the computation.
We revisit a fifteen years old
result about computing circumscription, showing that it can be improved in the
same way.
We provide hints in order to apply this forgetting method also to other
logical formalisms.
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