On Q

Autor: Visser, A., OFR - Theoretical Philosophy, LS Logica en grondslagen v.d. wiskunde
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: Soft Computing, 21(1), 39. Springer Verlag
Soft Computing, 21. Springer Verlag
ISSN: 1433-7479
1432-7643
Popis: In this paper we study the theory Q. We prove a basic result that says that, in a sense explained in the paper, Q can be split into two parts. We prove some consequences of this result. (i) Q is not a poly-pair theory. This means that, in a strong sense, pairing cannot be defined in Q. (ii) Q does not have the Pudlak Property. This means that there two interpretations of $$\mathsf{S}^1_2$$S21 in Q which do not have a definably isomorphic cut. (iii) Q is not sententially equivalent with $$\mathsf{PA}^-$$PA-. This tells us that we cannot do much better than mutual faithful interpretability as a measure of sameness of Q and $$\mathsf{PA}^-$$PA-. We briefly consider the idea of characterizing Q as the minimal-in-some-sense theory of some kind modulo some equivalence relation. We show that at least one possible road towards this aim is closed.
Databáze: OpenAIRE