centering figure

Question

I want to put this figure (Matrix) at the center but I can't, even though the title is centered:

How to do this please?

I have this code :

\begin{center}
\begin{figure}[H]
        \begin{center}
                    \[
                    \begin{blockarray}{cccccc}
                    123 & 12,3 & 13,2 & 1,23 & 1,2,3\\
                    \begin{block}{(ccccc)c}
                      0 & 1 & 1 & 1 & 0 & 123 \\
                      1 & 0 & 0 & 0 & 1 & 12,3 \\
                      1 & 0 & 0 & 0 & 1 & 13,2 \\
                      1 & 0 & 0 & 0 & 1 & 1,23 \\
                      0 & 1 & 1 & 1 & 0 & 1,2,3 \\
                    \end{block}
                    \end{blockarray}
                    \]
        \end{center}

 \caption{ Matrice d'adjacence de treillis de 5 partitions de $E = \{1,2,3\}$}
\end{figure}
\end{center}

Answer 1

You have too many center environments:

\begin{figure}
\centering
$\begin{blockarray}{cccccc}
123 & 12,3 & 13,2 & 1,23 & 1,2,3\\
\begin{block}{(ccccc)c}
0 & 1 & 1 & 1 & 0 & 123 \\
1 & 0 & 0 & 0 & 1 & 12,3 \\
1 & 0 & 0 & 0 & 1 & 13,2 \\
1 & 0 & 0 & 0 & 1 & 1,23 \\
0 & 1 & 1 & 1 & 0 & 1,2,3 \\
\end{block}
\end{blockarray}$
\caption{Matrice d'adjacence de treillis de 5 partitions de $E = \{1,2,3\}$}
\end{figure}

I've removed the [H] specification that I usually recommend not to use, particularly with big objects such as this.