Inverses for normal modal operators

Given a 1-ary sentence operator O, we describe L - another 1-ary operator - as a left inverse of O in a given logic if in that logic every formula φ is provably equivalent to LOφ. Similarly R is a right inverse of O if φ is always provably equivalent to ORφ. We investigate the behaviour of left and...

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Main Authors: Humberstone, L, Williamson, T
Other Authors: Institute of Philosophy and Sociology of the Polish Academy of Sciences
Format: Journal article
Language:English
Published: Springer 1997
Subjects:
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author Humberstone, L
Williamson, T
author2 Institute of Philosophy and Sociology of the Polish Academy of Sciences
author_facet Institute of Philosophy and Sociology of the Polish Academy of Sciences
Humberstone, L
Williamson, T
author_sort Humberstone, L
collection OXFORD
description Given a 1-ary sentence operator O, we describe L - another 1-ary operator - as a left inverse of O in a given logic if in that logic every formula φ is provably equivalent to LOφ. Similarly R is a right inverse of O if φ is always provably equivalent to ORφ. We investigate the behaviour of left and right inverses for O taken as the □ operator of various normal modal logics, paying particular attention to the conditions under which these logics are conservatively extended by the addition of such inverses, as well as to the question of when, in such extensions, the inverses behave as normal modal operators in their own right.
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spelling oxford-uuid:e201626d-f741-44b6-ab4f-ee7d8be42b3e2022-03-27T09:58:08ZInverses for normal modal operatorsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:e201626d-f741-44b6-ab4f-ee7d8be42b3ePhilosophyEnglishOxford University Research Archive - ValetSpringer1997Humberstone, LWilliamson, TInstitute of Philosophy and Sociology of the Polish Academy of SciencesGiven a 1-ary sentence operator O, we describe L - another 1-ary operator - as a left inverse of O in a given logic if in that logic every formula φ is provably equivalent to LOφ. Similarly R is a right inverse of O if φ is always provably equivalent to ORφ. We investigate the behaviour of left and right inverses for O taken as the □ operator of various normal modal logics, paying particular attention to the conditions under which these logics are conservatively extended by the addition of such inverses, as well as to the question of when, in such extensions, the inverses behave as normal modal operators in their own right.
spellingShingle Philosophy
Humberstone, L
Williamson, T
Inverses for normal modal operators
title Inverses for normal modal operators
title_full Inverses for normal modal operators
title_fullStr Inverses for normal modal operators
title_full_unstemmed Inverses for normal modal operators
title_short Inverses for normal modal operators
title_sort inverses for normal modal operators
topic Philosophy
work_keys_str_mv AT humberstonel inversesfornormalmodaloperators
AT williamsont inversesfornormalmodaloperators