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\begin{document}

\author{Karl Grosse-Erdmann\\ Institut de Math\'ematique\\ Universit\'e de Mons\\ Le Pentagone\\ 7000~Mons\\
Belgium\\kg.grosse-erdmann@umons.ac.be}

\date{}

\title{Lineability in summability}

\maketitle

\begin{abstract}
In summability, and especially so in the theory of sequence spaces, one usually deals with linear phenomena. But this is not always the case. For example, the sum of two conditionally convergent series need not be conditionally convergent. Can one find, even in such cases, some linear structure? We report on some recent answers to this question.
\end{abstract}


















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