BASIS THEOREMS FOR Sigma(1)(2)-SETS

Chong, CT; Wu, LZ; Yu, L

Chong, CT (reprint author), Natl Univ Singapore, Fac Sci, Dept Math, Singapore 119076, Singapore.

JOURNAL OF SYMBOLIC LOGIC, 2019; 84 (1): 376

Abstract

We prove the following two basis theorems for Sigma(1)(2)-sets of reals: (1) Every nonthin Sigma(1)(2)-set has a perfect Delta(1)(2)-subset if and onl......

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