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Proof
Take Then
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and therefore, by 2.5
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Since we get from this
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Again, by 2.5
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Therefore the definition of yields
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The Three Circles Theorem gives for small enough
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It follows that, choosing so that
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we obtain
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Further, since , we get from
2.2 that
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Inserting this into 2.7 we finally arrive at
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The proposition follows by comparing this inequality with
2.6.