TY - JOUR
T1 - Classical provability of uniform versions and intuitionistic provability
AU - Fujiwara, Makoto
AU - Kohlenbach, Ulrich
PY - 2015/5/1
Y1 - 2015/5/1
N2 - Along the line of Hirst-Mummert and Dorais , we analyze the relationship between the classical provability of uniform versions Uni(S) of Π2-statements S with respect to higher order reverse mathematics and the intuitionistic provability of S. Our main theorem states that (in particular) for every Π2-statement S of some syntactical form, if its uniform version derives the uniform variant of ACA over a classical system of arithmetic in all finite types with weak extensionality, then S is not provable in strong semi-intuitionistic systems including bar induction BI in all finite types but also nonconstructive principles such as Konig's lemma KL and uniform weak Konig's lemma UWKL. Our result is applicable to many mathematical principles whose sequential versions imply ACA.
AB - Along the line of Hirst-Mummert and Dorais , we analyze the relationship between the classical provability of uniform versions Uni(S) of Π2-statements S with respect to higher order reverse mathematics and the intuitionistic provability of S. Our main theorem states that (in particular) for every Π2-statement S of some syntactical form, if its uniform version derives the uniform variant of ACA over a classical system of arithmetic in all finite types with weak extensionality, then S is not provable in strong semi-intuitionistic systems including bar induction BI in all finite types but also nonconstructive principles such as Konig's lemma KL and uniform weak Konig's lemma UWKL. Our result is applicable to many mathematical principles whose sequential versions imply ACA.
UR - http://www.scopus.com/inward/record.url?scp=84929664147&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84929664147&partnerID=8YFLogxK
U2 - 10.1002/malq.201300056
DO - 10.1002/malq.201300056
M3 - Article
AN - SCOPUS:84929664147
SN - 0942-5616
VL - 61
SP - 132
EP - 150
JO - Mathematical Logic Quarterly
JF - Mathematical Logic Quarterly
IS - 3
ER -