Skip to main content\( \newcommand{\MyTikzmark}[2]{
\tikz[overlay,remember picture,baseline] \node [anchor=base] (#1) {$#2$};}
\newcommand{\DrawVLine}[3][]{
\begin{tikzpicture}[overlay,remember picture]
\draw[shorten \lt =0.3ex, #1] (#2.north) -- (#3.south);
\end{tikzpicture}
}
\newcommand{\DrawHLine}[3][]{
\begin{tikzpicture}[overlay,remember picture]
\draw[shorten \lt =0.2em, #1] (#2.west) -- (#3.east);
\end{tikzpicture}
}
\newcommand{\lt}{<}
\newcommand{\gt}{>}
\newcommand{\amp}{&}
\definecolor{fillinmathshade}{gray}{0.9}
\newcommand{\fillinmath}[1]{\mathchoice{\colorbox{fillinmathshade}{$\displaystyle \phantom{\,#1\,}$}}{\colorbox{fillinmathshade}{$\textstyle \phantom{\,#1\,}$}}{\colorbox{fillinmathshade}{$\scriptstyle \phantom{\,#1\,}$}}{\colorbox{fillinmathshade}{$\scriptscriptstyle\phantom{\,#1\,}$}}}
\)
