Reverse Mathematics, Archimedean Classes, and Hahn’s Theorem
نویسنده
چکیده
Archimedean classes and convex subgroups play important roles in the study of ordered groups. In this paper, we show that ACA0 is equivalent to the existence of a set of representatives for the Archimedean classes of an ordered abelian group. Hahn’s Theorem is the strongest known tool for classifying orders on abelian groups. It states that every ordered abelian group can be embedded into products of the additive group of the reals. We show that Hahn’s Theorem is also equivalent to ACA0. §
منابع مشابه
A New Approach to Caristi's Fixed Point Theorem on Non-Archimedean Fuzzy Metric Spaces
In the present paper, we give a new approach to Caristi's fixed pointtheorem on non-Archimedean fuzzy metric spaces. For this we define anordinary metric $d$ using the non-Archimedean fuzzy metric $M$ on a nonemptyset $X$ and we establish some relationship between $(X,d)$ and $(X,M,ast )$%. Hence, we prove our result by considering the original Caristi's fixedpoint theorem.
متن کاملFixed point approach to the Hyers-Ulam-Rassias approximation of homomorphisms and derivations on Non-Archimedean random Lie $C^*$-algebras
In this paper, using fixed point method, we prove the generalized Hyers-Ulam stability of random homomorphisms in random $C^*$-algebras and random Lie $C^*$-algebras and of derivations on Non-Archimedean random C$^*$-algebras and Non-Archimedean random Lie C$^*$-algebras for the following $m$-variable additive functional equation: $$sum_{i=1}^m f(x_i)=frac{1}{2m}left[sum_{i=1}^mfle...
متن کاملFUZZY QUASI-METRIC VERSIONS OF A THEOREM OF GREGORI AND SAPENA
We provide fuzzy quasi-metric versions of a fixed point theorem ofGregori and Sapena for fuzzy contractive mappings in G-complete fuzzy metricspaces and apply the results to obtain fixed points for contractive mappingsin the domain of words.
متن کاملNon-Archimedean fuzzy metric spaces and Best proximity point theorems
In this paper, we introduce some new classes of proximal contraction mappings and establish best proximity point theorems for such kinds of mappings in a non-Archimedean fuzzy metric space. As consequences of these results, we deduce certain new best proximity and fixed point theorems in partially ordered non-Archimedean fuzzy metric spaces. Moreover, we present an example to illustrate the us...
متن کاملAlmost Multi-Cubic Mappings and a Fixed Point Application
The aim of this paper is to introduce $n$-variables mappings which are cubic in each variable and to apply a fixed point theorem for the Hyers-Ulam stability of such mapping in non-Archimedean normed spaces. Moreover, a few corollaries corresponding to some known stability and hyperstability outcomes are presented.
متن کامل