## Journal of Symbolic Logic

### Interpolation for first order $S5$

Melvin Fitting

#### Abstract

An interpolation theorem holds for many standard modal logics, but first order $S5$ is a prominent example of a logic for which it fails. In this paper it is shown that a first order $S5$ interpolation theorem can be proved provided the logic is extended to contain propositional quantifiers. A proper statement of the result involves some subtleties, but this is the essence of it.

#### Article information

Source
J. Symbolic Logic, Volume 67, Issue 2 (2002), 621-634.

Dates
First available in Project Euclid: 18 September 2007

https://projecteuclid.org/euclid.jsl/1190150101

Digital Object Identifier
doi:10.2178/jsl/1190150101

Mathematical Reviews number (MathSciNet)
MR1905158

Zentralblatt MATH identifier
1009.03013

#### Citation

Fitting, Melvin. Interpolation for first order $S5$. J. Symbolic Logic 67 (2002), no. 2, 621--634. doi:10.2178/jsl/1190150101. https://projecteuclid.org/euclid.jsl/1190150101