3: Litigio

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( \newcommand{\kernel}{\mathrm{null}\,}\) $\newcommand{\range}{\mathrm{range}\,}$

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$\newcommand{\RealPart}{\mathrm{Re}}$

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$\newcommand{\norm}[1]{\| #1 \|}$

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$\newcommand{\Span}{\mathrm{span}}$ $\newcommand{\AA}{\unicode[.8,0]{x212B}}$

$\newcommand{\vectorA}[1]{\vec{#1}}      % arrow$

$\newcommand{\vectorAt}[1]{\vec{\text{#1}}}      % arrow$

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$\newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} }$

$\newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}}$

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