Math & Science ⇒ multi-column matrix headings

[maurolust]

Hi,

I want to display a mock-up of a matrix while making it a clear distinction between the structure in the two parts of a matrix. I made an almost successful attempt, but it resulted in unmatching parenthesis sizes, in addition to other alignment problems.

The minimal working examples show tiny matrices where the problem is quite evident.

Code: Select all

\documentclass{article}
\usepackage{amsmath}
\begin{document}

\[
\begin{array}{r |c|c|}
    &  \mathbf{H^{\;(1)}_{m \times k}} &  \mathbf{H^{\;(2)}_{m \times k}}  \\
    {\bf H}_\textrm{IRA}= & 
        \left(\overbrace{
            \begin{array}{ccc}
                \text{{\scriptsize{1}}} &  &\text{{\scriptsize{1}}}\\
                \text{{\scriptsize{1}}} & \text{{\footnotesize{1}}} &\\
                \text{{\scriptsize{1}}}&  & \\
            \end{array} }
        \right.
        &
        \left.\overbrace{
            \begin{array}{ccc}
                \text{{\scriptsize{1}}} &  &\text{\Huge{0}}\\
                \text{{\scriptsize{1}}} & \text{{\scriptsize{1}}} &\\
                \text{\Huge{0}}&  \text{{\scriptsize{1}}} &\text{{\scriptsize{1}}}
            \end{array} }
        \right)
\end{array}
\]
\end{document}

I tried another approach that allowed me to match the parenthesis, but the vertical alignment issues persists and the labels are not centered above the submatrices. Any suggestions? I'm including a picture of the actual matrix I want to display, build using the first method. It looks ok, but I didn't like the unmatching parenthesis sizes.

Code: Select all

\documentclass{article}
\usepackage{amsmath}
\begin{document}

\[
\begin{array}{r |c|}
    &
    \begin{array}{|c|c|}
        \hfill\mathbf{H^{\;(1)}_{m \times k}}\hfill & \hfill\mathbf{H^{\;(2)}_{m \times k}}\hfill
    \end{array}\\

    {\bf H}_\textrm{IRA} = &
    \left(\begin{array}{c|c}
           \overbrace{\begin{array}{ccc}
                          \text{{\scriptsize{1}}} &  &\text{{\scriptsize{1}}}\\
                          \text{{\scriptsize{1}}} & \text{{\footnotesize{1}}} &\\
                          \text{{\scriptsize{1}}}&  & \\
                      \end{array} }
    &
           \overbrace{\begin{array}{ccc}
                        \text{{\scriptsize{1}}} &  &\text{\Huge{0}}\\
                        \text{{\scriptsize{1}}} & \text{{\scriptsize{1}}} &\\
                        \text{\Huge{0}}&  \text{{\scriptsize{1}}} &\text{{\scriptsize{1}}}
                      \end{array} }
          \end{array}\right)\\

\end{array}
\]
\end{document}

God bless you

[php1ic]

Not sure if this is what you want, but I have tricked latex into aligning things by using white text.

Code: Select all

\documentclass{article}
\usepackage{amsmath,color}
\begin{document}
\[
\mathbf{H}_{\textrm{IRA}} =
\begin{matrix}
\mathbf{H^{(1)}_{m\times k}} & \mathbf{H^{(2)}_{m\times k}}\\
\left(\overbrace{\begin{matrix}1&\textrm{\Huge{{\color{white}{1}}}}&1\\1&1&\textrm{\Huge{{\color{white}{1}}}}\\1&&\textrm{\Huge{{\color{white}{1}}}}\end{matrix}}\right.
&
\left.\overbrace{\begin{matrix}1&&\textrm{\Huge{0}}\\1&1&\textrm{\Huge{{\color{white}{1}}}}\\\textrm{\Huge{0}}&1&1\end{matrix}}\right)
\end{matrix}
\]
\end{document}

as long as each row of the two sub matrices contains a big number then alignment seems to work.

EDIT: I can't work out exactly what you want from the picture, but will have a go if you tell me the values of m and k and the cells that contain a huge 0.

[maurolust]

@ php1ic
Thank you very much.

I think your solution is very close to what I need, maybe the white text will leave some "evidence" (mouse over, text selection, etc) but the effect would be pretty much what I want: a nicely formatted matrix. Maybe there is an invisible text command?

The values of k and m are 6 and 6, I think. I just wanted to pass the impression that the right section has a staircase shape and the left section is sparse and doesn't follow any visible pattern.

[php1ic]

I hadn't thought about what would happen with mouse over,

Code: Select all

\phantom{}

seems to be exactly what you want, it uses the space that would be needed, but doesn't print anything. This piece of code produces the matrix that was in your first post.

Code: Select all

\[
\mathbf{H}_{\textrm{IRA}} =
\begin{matrix}
\mathbf{H^{(1)}_{m\times k}}&\mathbf{H^{(2)}_{m\times k}}\\
\left(
\overbrace{\begin{matrix}
1&\phantom{\textrm{\Huge{0}}}&&1&&\\
&&\textrm{\Huge{0}}&&1&\textrm{\Huge{0}}\\
\textrm{\Huge{0}}&&1&&&1\\
1&&&&\textrm{\Huge{0}}&\\
&&\textrm{\Huge{0}}&&&1\\
&1&\phantom{\textrm{\Huge{0}}}&&1&
\end{matrix}}
\right.
&
\left.\overbrace{\begin{matrix}
1&&&&&\phantom{\textrm{\Huge{0}}}\\
1&1&&&\textrm{\Huge{0}}&\\
&1&\ddots&&&\phantom{\textrm{\Huge{0}}}\\
&&\ddots&1&&\phantom{\textrm{\Huge{0}}}\\
&\textrm{\Huge{0}}&&1&1&\\
\phantom{\textrm{\Huge{0}}}&&&&1&1
\end{matrix}}\right)
\end{matrix}
\]