Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2008/iii/paper-12/1/b/solution

The assertion is false for , but true for . For , take the jointly holomorphic right-hand side . Its solution with zero initial value is
At , the value zero has multiplicity at the origin. For , however, every zero is a simple zero: , and at a nonzero zero ,
Thus there is no zero of multiplicity anywhere, even though the simple zeros stay close to zero for small . When , part (a) gives exactly one zero counted with multiplicity in a small disc, so that zero is simple. Alternatively, the holomorphic implicit function theorem gives its holomorphic location as a function of .

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