ScalingStacks

Lemma 3.27 . [04BF]

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Lemma 3.27.

Let z1,…​zNz_{1},\ldots z_{N} be complex numbers, and a1,…​aNa_{1},\ldots a_{N} be fixed complex numbers with positive real parts, such that arg⁡a1>arg⁡a2>…>arg⁡aN\arg a_{1}>\arg a_{2}>\ldots>\arg a_{N}. Assume

Re​(zi)=Re​(ai),Im​∑1mzi≥Im​∑1mai,∑1Nzi=∑1Nai.\text{Re}(z_{i})=\text{Re}(a_{i}),\quad\text{Im}\sum_{1}^{m}z_{i}\geq\text{Im}\sum_{1}^{m}a_{i},\quad\sum_{1}^{N}z_{i}=\sum_{1}^{N}a_{i}.

Then ∑1N|zi|≥∑1N|ai|\sum_{1}^{N}|z_{i}|\geq\sum_{1}^{N}|a_{i}|.

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