Made proximal operator bold
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@ -1017,7 +1017,7 @@ $\gamma h\left( \tilde{\boldsymbol{x}} \right) $ has to be computed.
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It is then immediately approximated with gradient-descent:%
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%
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\begin{align*}
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\text{prox}_{\gamma h} \left( \tilde{\boldsymbol{x}} \right) &\equiv
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\textbf{prox}_{\gamma h} \left( \tilde{\boldsymbol{x}} \right) &\equiv
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\argmin_{\boldsymbol{t} \in \mathbb{R}^n}
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\left( \gamma h\left( \boldsymbol{t} \right) +
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\frac{1}{2} \lVert \boldsymbol{t} - \tilde{\boldsymbol{x}} \rVert \right)\\
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@ -274,12 +274,12 @@ desired \cite[Sec. 15.3]{ryan_lin_2009}.
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\textit{Proximal algorithms} are algorithms for solving convex optimization
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problems, that rely on the use of \textit{proximal operators}.
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The proximal operator $\text{prox}_f : \mathbb{R}^n \rightarrow \mathbb{R}^n$
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The proximal operator $\textbf{prox}_f : \mathbb{R}^n \rightarrow \mathbb{R}^n$
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of a function $f:\mathbb{R}^n \rightarrow \mathbb{R}$ is defined by
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\cite[Sec. 1.1]{proximal_algorithms}%
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%
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\begin{align*}
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\text{prox}_{\lambda f}\left( \boldsymbol{v} \right) = \argmin_{\boldsymbol{x}} \left(
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\textbf{prox}_{\lambda f}\left( \boldsymbol{v} \right) = \argmin_{\boldsymbol{x}} \left(
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f\left( \boldsymbol{x} \right) + \frac{1}{2\lambda}\lVert \boldsymbol{x}
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- \boldsymbol{v} \rVert_2^2 \right)
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.\end{align*}
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@ -300,7 +300,7 @@ and minimizing $g$ using the proximal operator
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%
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\begin{align*}
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\boldsymbol{x} \leftarrow \boldsymbol{x} - \lambda \nabla f\left( \boldsymbol{x} \right) \\
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\boldsymbol{x} \leftarrow \text{prox}_{\lambda g} \left( \boldsymbol{x} \right)
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\boldsymbol{x} \leftarrow \textbf{prox}_{\lambda g} \left( \boldsymbol{x} \right)
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,\end{align*}
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%
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Since $g$ is minimized with the proximal operator and is thus not required
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