Journal of Symbolic Logic

Unification in Intuitionistic Logic

Silvio Ghilardi

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Abstract

We show that the variety of Heyting algebras has finitary unification type. We also show that the subvariety obtained by adding it De Morgan law is the biggest variety of Heyting algebras having unitary unification type. Proofs make essential use of suitable characterizations (both from the semantic and the syntactic side) of finitely presented projective algebras.

Article information

Source
J. Symbolic Logic Volume 64, Issue 2 (1999), 859-880.

Dates
First available in Project Euclid: 6 July 2007

Permanent link to this document
http://projecteuclid.org/euclid.jsl/1183745815

JSTOR
links.jstor.org

Mathematical Reviews number (MathSciNet)
MR1777792

Zentralblatt MATH identifier
0930.03009

Subjects
Primary: 03B20: Subsystems of classical logic (including intuitionistic logic)
Secondary: 68T15: Theorem proving (deduction, resolution, etc.) [See also 03B35] 03B55: Intermediate logics 06D20: Heyting algebras [See also 03G25] 08B30: Injectives, projectives

Keywords
E-Unification Projective Heyting Algebras Exact Formulas Admissible Inference Rules

Citation

Ghilardi, Silvio. Unification in Intuitionistic Logic. J. Symbolic Logic 64 (1999), no. 2, 859--880. http://projecteuclid.org/euclid.jsl/1183745815.


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