We are a Working Group devoted to the discussion of historical and philosophical issues in symbolic logic, mathematics, and science. We meet on occasional Wednesday evenings for a talk and a lively discussion. The group is funded by the Doreen B. Townsend Center for the Humanities and the Department of Philosophy.

All members of the academic community are welcome to attend. We have regular participants in many different fields, including philosophy, mathematics, history of science, and psychology.

The group organizers are Wesley Holliday, John MacFarlane, Paolo Mancosu, Seth Yalcin, and Xueyin (Snow) Zhang.

### Our next event

April 25, 2024, 2-4 PM **(note special time)** in 234
Philosophy

*Sergei Artemov (CUNY Graduate Center)*

Two Models of Provability

Gödel’s modal logic approach to analyzing provability attracted a great deal of attention and eventually led to two distinct mathematical models. The first one is the modal logic GL, also known as the Provability Logic, which was shown in 1979 by Solovay to be the logic of the formal provability predicate. The second one is Gödel’s original modal logic of provability S4, together with its explicit counterpart, the Logic of Proofs LP, which was shown in 1995 by Artemov to provide an exact provability semantics for S4. These two models complement each other and cover a wide range of applications, from traditional proof theory to λ-calculi and formal epistemology.

Recommended reading: Artemov, S. (2007). On two models of
provability. In *Mathematical Problems from Applied Logic II: Logics
for the XXIst Century* (pp. 1-52). New York, NY: Springer New York.
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