A Note about Stabilization in $A_\R(\D)$

Abstract

It is shown that for $A_\R(\D)$ functions $f_1$ and $f_2$ with $$ \inf_{z\in\bar{\D}}(\abs{f_1(z)}+\abs{f_2(z)})\geqδ>0 $$ and $f_1$ being positive on real zeros of $f_2$ then there exists $A_\R(\D)$ functions $g_2$ and $g_1,g_1^{-1}$ with and $$ g_1f_1+g_2f_2=1\quad\forall z\in\bar{\D}. $$ This result is connected to the computation of the stable rank of the algebra $A_\R(\D)$ and to Control Theory.

5 pages, to appear in Math. Nachr

Cited by in corpus (2)

• The Bass and Topological Stable Ranks of $H^\infty_\R(\D)$ and $A_\R(\D)$
• The covering dimension of a distinguished subset of the spectrum $M(H^{\infty })$ of $H^{\infty }$ and the algebra of real-symmetric and continuous functions on $M(H^{\infty })$