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</script>The paper establishes some general conditions under wich a formula A(p) has only provable fixed points in Guaspari-Solovay modal logic of provability R. This result is used to give another proof of Parikh's theorem: For each natural number \(k\geq 1\) there is an arithmetical sentence A, provable in PA, such that \(\square^ kA\) has a much shorter proof than \(\square^ mA\) for any \(m
First-order arithmetic and fragments, provable fixed points, Guaspari-Solovay modal logic of provability, proof, Gödel numberings and issues of incompleteness, Parikh's theorem, Modal logic (including the logic of norms)
First-order arithmetic and fragments, provable fixed points, Guaspari-Solovay modal logic of provability, proof, Gödel numberings and issues of incompleteness, Parikh's theorem, Modal logic (including the logic of norms)
| citations This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 8 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Average | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Top 10% | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Average |
