Research output: Contribution to journal › Article › peer-review
Belnap–Dunn modal logics: truth constants vs. truth values. / Odintsov, Sergei P.; Speranski, Stanislav O.
In: Review of Symbolic Logic, 2019.Research output: Contribution to journal › Article › peer-review
}
TY - JOUR
T1 - Belnap–Dunn modal logics: truth constants vs. truth values
AU - Odintsov, Sergei P.
AU - Speranski, Stanislav O.
PY - 2019
Y1 - 2019
N2 - We shall be concerned with the modal logic BK — which is based on the Belnap–Dunn four-valued matrix, and can be viewed as being obtained from the least normal modal logic K by adding `strong negation'. Though all four values `truth', `falsity', `neither' and `both' are employed in its Kripke semantics, only the first two are expressible as terms. We show that expanding the original language of BK to include constants for `neither' or/and `both' leads to quite unexpected results. To be more precise, adding one of these constants has the effect of eliminating the respective value at the level of BK-extensions. In particular, if one adds both of these, then the corresponding lattice of extensions turns out to be isomorphic to that of ordinary normal modal logics.
AB - We shall be concerned with the modal logic BK — which is based on the Belnap–Dunn four-valued matrix, and can be viewed as being obtained from the least normal modal logic K by adding `strong negation'. Though all four values `truth', `falsity', `neither' and `both' are employed in its Kripke semantics, only the first two are expressible as terms. We show that expanding the original language of BK to include constants for `neither' or/and `both' leads to quite unexpected results. To be more precise, adding one of these constants has the effect of eliminating the respective value at the level of BK-extensions. In particular, if one adds both of these, then the corresponding lattice of extensions turns out to be isomorphic to that of ordinary normal modal logics.
KW - Many-Valued modal logic
KW - algebraic logic
KW - first-degree entailment
KW - strong negation
UR - http://www.scopus.com/inward/record.url?scp=85062032769&partnerID=8YFLogxK
U2 - 10.1017/S1755020319000121
DO - 10.1017/S1755020319000121
M3 - Article
JO - Review of Symbolic Logic
JF - Review of Symbolic Logic
SN - 1755-0203
ER -
ID: 39018026