English

Ring Of Real Analytic Functions on $[0,1]$

Commutative Algebra 2016-11-15 v2 Classical Analysis and ODEs Rings and Algebras

Abstract

We consider the ring of real analytic functions defined on [0,1][0,1], i.e. Cω[0,1]={f:[0,1]Rf is analytic on [0,1]}C^{\omega}[0,1] =\lbrace f :[0,1] \longrightarrow \mathbb{R} | f \text{ is analytic on } [0,1]\rbrace In this article, we explore the nature of ideals in this ring. It is well known that the ring C[0,1]C[0,1] of real valued continuous functions on [0,1][0,1] has precisely the following maximal ideals: For γ[0,1],Mγ:={fC[0,1]f(γ)=0}\text{For } \gamma \in [0,1], M_{\gamma} := \lbrace f \in C[0,1] | f(\gamma) =0\rbrace It has been proved that each such MγM_{\gamma} is infinitely generated, in-fact uncountably generated. Observe that Cω[0,1]C^{\omega}[0,1] is a subring of C[0,1]C[0,1] We prove that for any γ\gamma in [0,1][0,1], the contraction MγωM^{\omega}_{\gamma} of MγM_{\gamma} under the natural inclusion of Cω[0,1]C^{\omega}[0,1] in C[0,1]C[0,1] is again a maximal ideal (of Cω[0,1]C^{\omega}[0,1] ), and these are precisely all the maximal ideals of Cω[0,1]C^{\omega}[0,1]. Next we prove that each MγωM^{\omega}_{\gamma} is principal (though MγM_{\gamma} is uncountably generated). Surprisingly, this forces all the ideals of the ring Cω[0,1]C^{\omega}[0,1] to be singly generated, i.e. Cω[0,1]C^{\omega}[0,1] is a PID.

Keywords

Cite

@article{arxiv.1611.03667,
  title  = {Ring Of Real Analytic Functions on $[0,1]$},
  author = {Sagar Shrivastava and Vaibhav Pandey},
  journal= {arXiv preprint arXiv:1611.03667},
  year   = {2016}
}