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On the Π 1 1 ‐separation principle
Author(s) -
Montalbán Antonio
Publication year - 2008
Publication title -
mathematical logic quarterly
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.473
H-Index - 28
eISSN - 1521-3870
pISSN - 0942-5616
DOI - 10.1002/malq.200710049
Subject(s) - mathematics , axiom , separation (statistics) , axiom of choice , separation axiom , scheme (mathematics) , axiom independence , discrete mathematics , combinatorics , mathematical economics , set theory , computer science , mathematical analysis , statistics , set (abstract data type) , geometry , programming language
We study the proof‐theoretic strength of the Π 1 1 ‐separation axiom scheme, and we show that Π 1 1 ‐separation lies strictly in between the Δ 1 1 ‐comprehension and Σ 1 1 ‐choice axiom schemes over RCA 0 . (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)