Csdrhrt

I wish to write the following block matrix in LaTex.

I have been trying a bunch of stuff, but none of it seems to work. In particular, I tried the following:

begin{bmatrix}

0 & -1&        &         &          &        & 0    &         &       &         &\

1 & 0 &        &         &          &        &      &         &       &         &\

  &   & cdot  &         &          &        &      &         &       &         &\

  &   &        & cdot   &          &        &      &         &       &         &\

  &   &        &         & cdot    &        &      &         &       &         &\

  &   &        &         &          & 0      & 1    &         &       &         &\

  &   &        &         &          &-1      & 0    &         &       &         &\

  &   &        &         &          &        &      & cdot  &        &        &\

  &   &        &         &          &        &      &         & cdot &        &  \ 

  &   &        &         &          &        &      &         &        &  cdot & \

0 &   &        &         &          &        &      &         &        &         &  0\ 

end{bmatrix}

But this is pretty ugly and so any suggestions will be much appreciated.

Perhaps

$left(begin{array}{cccccc}

left[begin{array}{cc}

0 & 1\

-1 & 0

end{array}right] &  &  &  &  & 0\

 & ddots\

 &  & left[begin{array}{cc}

0 & 1\

-1 & 0

end{array}right]\

 &  &  & 0\

 &  &  &  & ddots\

0 &  &  &  &  & 0

end{array}right)$  

Just for the fun of it! :-)

documentclass{article}

usepackage{amsmath,array}



begin{document}



[

begin{pmatrix}

newcommand{lr}[1]{multicolumn{1}{|c}{#1}}

newcommand{rr}[1]{multicolumn{1}{c|}{#1}}

;

begin{array}{@{}*{10}{c}@{}}

cline{1-2}

lr{0} & rr{1} &&&&&&&& raisebox{-1em}[0pt][0pt]{$0$}\

lr{-1} & rr{0} \

cline{1-2}

&& ddots \

cline{4-5}

&&& lr{0} & rr{1} \

&&& lr{-1} & rr{0} \

cline{4-5}

&&&&& 0 \[-1ex]

&&&&&& ddots \

&&&&&&& 0 \[-1ex]

&&&&&&&& ddots \

multicolumn{2}{c}{0} &&&&&&&& 0

end{array}

;;

end{pmatrix}

]



end{document}

Here there is my proposal as the original picture using bmatx command that replace a boxed matrix.

documentclass{article}

usepackage{mathtools}

newcommand{bmatx}{boxed{begin{matrix} 0&  1  \ -1&  0end{matrix}}}



begin{document}

[

begin{pmatrix}

, bmatx&  &  &  &  & & & 0 \ 

 &  ddots&  &  &  & \ 

 &  &  bmatx &  &  & & \ 

 &  &  &  ddots&  & &\ 

 &  &  &  & 0 & &\ 

 &  &  &  &  &  & ddots\ 

0 &  &  &  &  &  & & 0 

end{pmatrix}

]



end{document}

The best code is provided thanks to the precious comment of @Bernard.

Here's another solution. It uses a pmatrix environment for the overall matrix and a custom macro called blockmat for the 2x2 inner matrices.

documentclass{article}

usepackage{array,amsmath}

newcommandblockmat{%

   begin{array}{|@{,}rr@{,}|}

     hline 0 & 1^{mathstrut} \ -1 & 0 \ hline

   end{array}}

begin{document}

[

begin{pmatrix}

blockmat &        &           &   &        & 0 \

          & ddots &           &   &        &   \

          &        & blockmat &   &        &   \

          &        &           & 0 &        &   \

          &        &           &   & ddots &   \

0         &        &           &   &        & 0 \  

end{pmatrix}

]

end{document}

Here's a solution using TikZ that will work in all kinds of context, not just matrices, to draw boxes. You just need to put tl in the point where the top-right corner is supposed to be and br where the bottom-right will be. You can also use any TikZ feature to modify your box. Obviously this needs to be fine tuned depending on what exactly you're using it for (spacing etc.).

newcounter{textbox}

deftl{stepcounter{textbox}tikzmarknode{athetextbox}{strut}}

defbr{tikzmarknode{bthetextbox}{strut}begin{tikzpicture}[overlay, remember picture]draw (athetextbox.north west) rectangle (bthetextbox.south east);end{tikzpicture}}

The spacing in this version is not optimized for matrices, but you can use

tikzmarknode{bthetextbox}{strut}begin{tikzpicture}[overlay, remember picture]draw ($(athetextbox.north west)+(-0.4arraycolsep,0ex)$) rectangle ($(bthetextbox.south east)+(0.4arraycolsep,0ex)$);end{tikzpicture}

to add extra space.

Full code:

documentclass{article}

usepackage{tikz}

usepackage{amsmath} 

usetikzlibrary{tikzmark,calc}

newcounter{textbox}

deftl{stepcounter{textbox}tikzmarknode{athetextbox}{strut}}

defbr{tikzmarknode{bthetextbox}{strut}begin{tikzpicture}[overlay, remember picture]draw (athetextbox.north west) rectangle (bthetextbox.south east);end{tikzpicture}}

begin{document}

[

begin{bmatrix}

tl0    &-1     &        &         &          &        &      &         &       &    0    \

1       & 0br  &        &         &          &        &      &         &       &         \

        &       & cdot  &         &          &        &      &         &       &         \

        &       &        & cdot   &          &        &      &         &       &         \

        &       &        &         & cdot    &        &      &         &       &         \

        &       &        &         &          &tl0    & 1    &         &       &         \

        &       &        &         &          &-1      & 0br &         &       &         \

        &       &        &         &          &        &      & cdot   &       &         \

        &       &        &         &          &        &      &         & cdot &         \ 

0       &       &        &         &          &        &      &         &       &  cdot  \

end{bmatrix}

]

end{document}