Expos\'e on a paper of Dronov and Kaplitzkii
Abstract
Dronov and Kaplitzki showed that every complemented subspace of a nuclear K\"othe space E with a regular basis of type (d1) has a basis so, in particular, solving the long standing problem whether any complemented subspace of the space (s) of rapidly decreasing sequences has a basis. We present a slightly modified version of their proof which shows that the range of every closed-range operator in E has a basis
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