Is this what you intended to display?
Using \$ ... \$
:
\$\require{enclose}\begin{array}{ccccccccc}
\Large{\enclose{circle}{A}} & \xrightarrow{0.1} & \Large{\enclose{circle}{B}} & \xrightarrow{0.2} & \Large{\enclose{circle}{C}} & \xleftarrow{0.3} & \Large{\enclose{circle}{D}} & \xleftarrow{0.4} & \Large{\enclose{circle}{E}}\\\
\scriptsize{0.5}\large{\downarrow} & \scriptsize{0.6}\large{\searrow} & \scriptsize{0.7}\large{\downarrow} & \scriptsize{0.8}\large{\nearrow} & \scriptsize{0.9}\large{\downarrow} & \scriptsize{0.1}\large{\swarrow} & \scriptsize{0.2}\large{\downarrow} & \scriptsize{0.3}\large{\nwarrow} & \scriptsize{0.4}\large{\downarrow}\\\
\Large{\enclose{circle}{F}} & \xrightarrow[0.5]{} & \Large{\enclose{circle}{G}} & \xrightarrow[0.6]{} & \Large{\enclose{circle}{H}} & \xleftarrow[0.7]{} & \Large{\enclose{circle}{I}} & \xleftarrow[0.8]{} & \Large{\enclose{circle}{J}}\\
\circlearrowright\tfrac12\\
\end{array}
\$
\$\require{enclose}\begin{array}{ccccccccc}
\Large{\enclose{circle}{A}} & \xrightarrow{0.1} & \Large{\enclose{circle}{B}} & \xrightarrow{0.2} & \Large{\enclose{circle}{C}} & \xleftarrow{0.3} & \Large{\enclose{circle}{D}} & \xleftarrow{0.4} & \Large{\enclose{circle}{E}}\\\
\scriptsize{0.5}\large{\downarrow} & \scriptsize{0.6}\large{\searrow} & \scriptsize{0.7}\large{\downarrow} & \scriptsize{0.8}\large{\nearrow} & \scriptsize{0.9}\large{\downarrow} & \scriptsize{0.1}\large{\swarrow} & \scriptsize{0.2}\large{\downarrow} & \scriptsize{0.3}\large{\nwarrow} & \scriptsize{0.4}\large{\downarrow}\\\
\Large{\enclose{circle}{F}} & \xrightarrow[0.5]{} & \Large{\enclose{circle}{G}} & \xrightarrow[0.6]{} & \Large{\enclose{circle}{H}} & \xleftarrow[0.7]{} & \Large{\enclose{circle}{I}} & \xleftarrow[0.8]{} & \Large{\enclose{circle}{J}}\\
\circlearrowright\tfrac12\\
\end{array}\$
Or $$ ... $$
for a 'block'/'region' (I don't know the correct terminology):
$$
\require{enclose}
\begin{array}{ccccccccc}
\Large{\enclose{circle}{A}} & \xrightarrow{0.1} & \Large{\enclose{circle}{B}} & \xrightarrow{0.2} & \Large{\enclose{circle}{C}} & \xleftarrow{0.3} & \Large{\enclose{circle}{D}} & \xleftarrow{0.4} & \Large{\enclose{circle}{E}}\\\
\scriptsize{0.5}\large{\downarrow} & \scriptsize{0.6}\large{\searrow} & \scriptsize{0.7}\large{\downarrow} & \scriptsize{0.8}\large{\nearrow} & \scriptsize{0.9}\large{\downarrow} & \scriptsize{0.1}\large{\swarrow} & \scriptsize{0.2}\large{\downarrow} & \scriptsize{0.3}\large{\nwarrow} & \scriptsize{0.4}\large{\downarrow}\\\
\Large{\enclose{circle}{F}} & \xrightarrow[0.5]{} & \Large{\enclose{circle}{G}} & \xrightarrow[0.6]{} & \Large{\enclose{circle}{H}} & \xleftarrow[0.7]{} & \Large{\enclose{circle}{I}} & \xleftarrow[0.8]{} & \Large{\enclose{circle}{J}}\\
\circlearrowright\tfrac12\\
\end{array}
$$
$$
\require{enclose}
\begin{array}{ccccccccc}
\Large{\enclose{circle}{A}} & \xrightarrow{0.1} & \Large{\enclose{circle}{B}} & \xrightarrow{0.2} & \Large{\enclose{circle}{C}} & \xleftarrow{0.3} & \Large{\enclose{circle}{D}} & \xleftarrow{0.4} & \Large{\enclose{circle}{E}}\\\
\scriptsize{0.5}\large{\downarrow} & \scriptsize{0.6}\large{\searrow} & \scriptsize{0.7}\large{\downarrow} & \scriptsize{0.8}\large{\nearrow} & \scriptsize{0.9}\large{\downarrow} & \scriptsize{0.1}\large{\swarrow} & \scriptsize{0.2}\large{\downarrow} & \scriptsize{0.3}\large{\nwarrow} & \scriptsize{0.4}\large{\downarrow}\\\
\Large{\enclose{circle}{F}} & \xrightarrow[0.5]{} & \Large{\enclose{circle}{G}} & \xrightarrow[0.6]{} & \Large{\enclose{circle}{H}} & \xleftarrow[0.7]{} & \Large{\enclose{circle}{I}} & \xleftarrow[0.8]{} & \Large{\enclose{circle}{J}}\\
\circlearrowright\tfrac12\\
\end{array}
$$
\$
rather than$
as the in-line delimiters. Note that your delimiters are not being removed, which indicates that MathJax isn't processing them as Math delimiters. The array environment is processed because any\begin{xyz} ... \end{xyz}
delimiters are treated as display math delimiters. \$\endgroup\$