Abstract
In a classical paper, F. Lettenmeyer [8] showed that a linear ordinary differential system with an irregular singular point at z = a,, may have several linearly independent solutions holomorphic at za , and estimated the number of such solutions. The Lettenmeyer theorem was extended to nonlinear systems by R. W. Bass [l], who effected a change of variables in order to apply Wintner’s fixed-point theorem for analytic mappings in a separable Hilbert space. Recent work of W. A. Harris, Jr., Y. Sibuya, and L. Weinberg [4, 61 has greatly simplified the proofs of the theorems of Lettenmeyer and Bass and has, in addition, yielded several theorems on systems of Briot-Bouquet type as corollaries. In a recent note [2], we developed analogues of some of these results for neutral functional differential systems (NFDS) of the form
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