Математическая логика, алгебра и теория чисел
Repetition-free and infinitary analytic calculi for first-order rational Pavelka logic
A. S. Gerasimov Peter the Great St.Petersburg Polytechnic University (SPbPU), 29, Polytechnicheskaya str., St. Petersburg, 195251, Russia
Аннотация:
We present an analytic hypersequent calculus
$\mathrm{G}^3$Ł
$\forall$ for first-order infinite-valued Łukasiewicz logic Ł
$\forall$ and for an extension of it, first-order rational Pavelka logic
$\mathrm{RPL}\forall$; the calculus is intended for bottom-up proof search. In
$\mathrm{G}^3$Ł
$\forall$, there are no structural rules, all the rules are invertible, and designations of multisets of formulas are not repeated in any premise of the rules. The calculus
$\mathrm{G}^3$Ł
$\forall$ proves any sentence that is provable in at least one of the previously known analytic calculi for Ł
$\forall$ or
$\mathrm{RPL}\forall$, including Baaz and Metcalfe's hypersequent calculus
$\mathrm{G}$Ł
$\forall$ for Ł
$\forall$. We study proof-theoretic properties of
$\mathrm{G}^3$Ł
$\forall$ and thereby provide foundations for proof search algorithms. We also give the first correct proof of the completeness of the
$\mathrm{G}$Ł
$\forall$-based infinitary calculus for prenex Ł
$\forall$-sentences, and establish the completeness of a
$\mathrm{G}^3$Ł
$\forall$-based infinitary calculus for prenex
$\mathrm{RPL}\forall$-sentences.
Ключевые слова:
many-valued logic, mathematical fuzzy logic, first-order infinite-valued Łukasiewicz logic, first-order rational Pavelka logic, proof theory, hypersequent calculus, proof search, infinitary calculus.
УДК:
510.644,
510.662
MSC: 03B50,
03B52,
03F07,
03B35 Поступила 30 марта 2020 г., опубликована
18 ноября 2020 г.
DOI:
10.33048/semi.2020.17.127