1 Department of Mathematics, Technical University of Denmark2 Department of Applied Mathematics and Computer Science, Technical University of Denmark
On Accumulation of Stretching Rays
In this thesis we study the structure of the boundary of the cubic connectedness locus viewed from the escape locus; i.e. the limiting behaviour of stretching rays.We prove that the stretching ray through a polynomial P with no parabolic fixed point of multiplier one accumulates a cubic polynomial with one parabolic fixed point of multiplier one, the other fixed point repelling, and each critical point in the parabolic basin or in a (super)-attracting basin only if a critical point of P belongs to a fixed ray of the filled Julia set of P. This applies to the locus of cubic polynomials with both critical points in the immediate basin of parabolic fixed points of multiplier one.By using a holomorphic index argument we prove that there are regions in the boundary of the cubic connectedness locus where no strtching rays accumulate.Finally we introduce the concept of a ground wind at polynomials with a parabolic cycle. We give an example of a non-vanishing cubic ground wind. It follows that the wring operator is discontinuous in degree three.
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Department of Mathematics, Technical University of Denmark, 1997