The geometry of sum-preserving permutations
Several authors in the past have given characterizations of those permutations \(\sigma\) of the set of positive integers such that for every convergent series \(\sum a_ i\), the series \(\sum a_{\sigma (i)}\) converges. The present paper gives some further such characterizations, some additional properties of such permutations, and a few open questions.
scientific article; zbMATH DE number 4136645