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Mathematical logic, algebra and number theory
Effectively infinite classes of numberings and fixed point theorems
M. Kh. Faizrahmanovab a Kazan Federal University, Kremlevskaya str., 18, 420008, Kazan, Russia
b Volga Region Scientific-Educational Centre of Mathematics,
Kremlevskaya str., 35,
420008, Kazan, Russia
Abstract:
In this paper, we prove a sufficient condition for the effective infinity of classes of complete and precomplete numberings, as well as numberings satisfying the recursion theorem, of computable families. A sufficient condition for the effective infinity of classes of non-precomplete numberings of computable families satisfying the recursion theorem is also obtained. These conditions are satisfied by the family of all c.e. sets and the family of graphs of all partially computable functions. For finite families of c.e. sets, we prove a criterion for the effective infinity of classes of their numberings that satisfy the recursion theorem. Finally, it is established that the classes of complete and precomplete numberings of finite families of c.e. sets are not effectively infinite.
Keywords:
computable numbering, complete numbering, precomplete numbering, recursion theorem, effective infinity.
Received January 19, 2023, published December 28, 2023
Citation:
M. Kh. Faizrahmanov, “Effectively infinite classes of numberings and fixed point theorems”, Sib. Èlektron. Mat. Izv., 20:2 (2023), 1519–1536
Linking options:
https://www.mathnet.ru/eng/semr1657 https://www.mathnet.ru/eng/semr/v20/i2/p1519
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Abstract page: | 58 | Full-text PDF : | 30 | References: | 22 |
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