ON IDEMPOTENT ULTRAFILTERS IN HIGHER-ORDER REVERSE MATHEMATICS
نویسندگان
چکیده
منابع مشابه
Non-principal Ultrafilters, Program Extraction and Higher Order Reverse Mathematics
We investigate the strength of the existence of a non-principal ultrafilter over fragments of higher order arithmetic. Let (U) be the statement that a non-principal ultrafilter on N exists and let ACA0 be the higher order extension of ACA0. We show that ACA0 + (U) is Π2-conservative over ACA0 and thus that ACA0 +(U) is conservative over PA. Moreover, we provide a program extraction method and s...
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ژورنال
عنوان ژورنال: The Journal of Symbolic Logic
سال: 2015
ISSN: 0022-4812,1943-5886
DOI: 10.1017/jsl.2014.58