Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
Computably and punctually universal spaces. / Bagaviev, Ramil; Batyrshin, Ilnur I.; Bazhenov, Nikolay и др.
в: Annals of Pure and Applied Logic, Том 176, № 1, 103491, 01.2025.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
}
TY - JOUR
T1 - Computably and punctually universal spaces
AU - Bagaviev, Ramil
AU - Batyrshin, Ilnur I.
AU - Bazhenov, Nikolay
AU - Bushtets, Dmitry
AU - Dorzhieva, Marina
AU - Koh, Heer Tern
AU - Kornev, Ruslan
AU - Melnikov, Alexander G.
AU - Ng, Keng Meng
PY - 2025/1
Y1 - 2025/1
N2 - We prove that the standard computable presentation of the space C[0,1] of continuous real-valued functions on the unit interval is computably and punctually (primitively recursively) universal. From the perspective of modern computability theory, this settles a problem raised by Sierpiński in the 1940s. We prove that the original Urysohn's construction of the universal separable Polish space U is punctually universal. We also show that effectively compact, punctual Stone spaces are punctually homeomorphically embeddable into Cantor space 2ω; note that we do not require effective compactness be primitive recursive. We also prove that effective compactness cannot be dropped from the premises by constructing a counterexample.
AB - We prove that the standard computable presentation of the space C[0,1] of continuous real-valued functions on the unit interval is computably and punctually (primitively recursively) universal. From the perspective of modern computability theory, this settles a problem raised by Sierpiński in the 1940s. We prove that the original Urysohn's construction of the universal separable Polish space U is punctually universal. We also show that effectively compact, punctual Stone spaces are punctually homeomorphically embeddable into Cantor space 2ω; note that we do not require effective compactness be primitive recursive. We also prove that effective compactness cannot be dropped from the premises by constructing a counterexample.
KW - Computable Polish space
KW - Continuous functions on the unit interval
KW - Primitive recursive analysis
KW - Punctual
KW - Universal spaces
UR - https://www.mendeley.com/catalogue/201223d0-9465-375e-b32f-b1fcbc65209a/
UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85200913507&origin=inward&txGid=91f4204e4737a9462e1b7b10407409d2
U2 - 10.1016/j.apal.2024.103491
DO - 10.1016/j.apal.2024.103491
M3 - Article
VL - 176
JO - Annals of Pure and Applied Logic
JF - Annals of Pure and Applied Logic
SN - 0168-0072
IS - 1
M1 - 103491
ER -
ID: 62768678