Approximation by Banded Matrices and Application to Wireless CommunicationsAndreas Klotz given at strobl07 (19.06.07) id: 832 length: min status: accepted type: poster LINK-Presentation: http://univie.ac.at/nuhag-php/dateien/talks/832_strobl07_poster_newformat.pdf ABSTRACT: TeX: Banach algebras of matrices $A(i,k)_{i,k \in \Z^d}$ with some kind of off-diagonal decay arise naturally in applications. Starting points of our research have been the following questions: {Can off diagonal decay of matrices be characterized by the ``quality of approximation'' with banded matrices (matrices with $A(i,k)=0$ if $\abs{i-k}>n$ for an $n$)?} This falls into the framework of approximation theory. {Do the approximation spaces of matrix algebras inherit special properties? Are they, in particular, again Banach Algebras s? Does a matrix inverse $A^{-1}$ have the same approximation quality as $A$? } This asks for \emph{spectral invariance} properties of the approximation spaces. |