Coding of real-valued continuous functions under WKL$\mathsf {WKL}$

被引:0
|
作者
Kawai, Tatsuji [1 ]
机构
[1] Kochi Univ, Dept Informat Sci, 2-5-1 Akebono Cho, Kochi 7808520, Japan
基金
日本学术振兴会;
关键词
FAN THEOREM; UNIFORM; LEMMA;
D O I
10.1002/malq.202200031
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
In the context of constructive reverse mathematics, we show that weak Konig's lemma (WKL$\mathsf {WKL}$) implies that every pointwise continuous function f:[0,1]& RARR;R$f : [0,1]\rightarrow \mathbb {R}$ is induced by a code in the sense of reverse mathematics. This, combined with the fact that WKL$\mathsf {WKL}$ implies the Fan theorem, shows that WKL$\mathsf {WKL}$ implies the uniform continuity theorem: every pointwise continuous function f:[0,1]& RARR;R$f : [0,1]\rightarrow \mathbb {R}$ has a modulus of uniform continuity. Our results are obtained in Heyting arithmetic in all finite types with quantifier-free axiom of choice.
引用
收藏
页码:370 / 391
页数:22
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