Plot of the <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \rho }"><semantics><mrow class="MJX-TeXAtom-ORD"><mstyle displaystyle="true" scriptlevel="0"><mi>ρ<!-- ρ --></mi></mstyle></mrow><annotation encoding="application/x-tex">{\displaystyle \rho }</annotation></semantics></math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/1f7d439671d1289b6a816e6af7a304be40608d64" class="mwe-math-fallback-image-inline" aria-hidden="true" style="vertical-align: -0.838ex; width:1.202ex; height:2.176ex;" alt="{\displaystyle \rho }"></span>-function used for the robust Huber-k-estimator (k=1.28)
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This  <a href="https://en.wikipedia.org/wiki/drawing" class="extiw" title="w:drawing">drawing</a> was created with <a href="https://en.wikipedia.org/wiki/Inkscape" class="extiw" title="w:Inkscape">Inkscape</a> by xorx .