Question : Is it possible to use tikzcd code in MO posts?
There are information for drawing diagrams using AMScd
$\require{AMScd}$
\begin{CD}
A @>a>> B\\
@V b V V= @VV c V\\
C @>>d> D
\end{CD}
but could not find one for tikzcd
I want to compile following tikz code.
\begin{tikzcd}
&&\mathcal{H}_1\ar[dd,shift left]\ar[dd,shift right]\\
&
P\ar[dl,"\pi"']\ar[dr,"a_R"]
& \\[1.5em]
B & & \mathcal{H}_0
\end{tikzcd}