enter image description here

I want to get the above diagram in Latex, but I don't know how to edit it. Any help will be appreciated. I post my effort in the following way.

&& \binom{\alpha_2}{0} \ar[dr]  && \ar[l] \binom{\alpha_2}{1}  \ar[dr] && 
\ar[l] \binom{\alpha_2}{2}   \\
&  \ar@{.>}[ur]\binom{\alpha_1}{0}  && \ar[l] \binom{\alpha_1}{1} \ar[ur]   
&& \ar[l] \binom{\alpha_1}{2} \ar@{.>}[ur]   \\
  • @Daisy Start with your document class, then add the necessary packages to make your snippet that you provided in your question work. So, that it will make others life way easier. May 17, 2017 at 9:35
  • Does it have to be done in xy ?
    – Thruston
    May 17, 2017 at 12:51
  • @ Thruston, No, can you help me? You can also give me another codes
    – Daisy
    May 17, 2017 at 14:28

2 Answers 2


Since xy package is not mandatory for you, I suggest a solution with a tikz matrix.

    mypoint/.style={circle, fill=black},
    middlearrow/.style={% this code is from https://tex.stackexchange.com/a/39283/101651
            mark= at position 0.5 with {\arrow[scale=2]{#1}} ,

    \matrix[column sep=2.5em, row sep=8ex, inner sep=0pt, minimum width=4pt] {%
        %first row
        \node (startrow1) {}; &&
        \node[mypoint, label={[above,yshift=2pt]$\beta_{1}$}] (B1) {}; &&
        \node[mypoint, label={[above,yshift=2pt]$\beta_{2}$}] (B2) {}; && 
        \node[mypoint, label={[above,yshift=2pt]$\beta_{3}$}] (B3) {}; && 
        \node[text width=3em, align=center] (endrow1) {$\beta$};
        %second row
        \node (startrow2) {}; &
        \node[mypoint, label={[below,yshift=-8pt]$\alpha_{1}$}] (A1) {}; &&
        \node[mypoint, label={[below,yshift=-8pt]$\alpha_{2}$}] (A2) {}; && 
        \node[mypoint, label={[below,yshift=-8pt]$\alpha_{3}$}] (A3) {}; &&& 
        \node[text width=3em, align=center] (endrow2) {$\alpha$};
    \draw[dashed] (startrow1) -- (B1)
    (B3) -- (endrow1)
    (startrow2) -- (A1)
    (A3) -- (endrow2);
    \draw[middlearrow={<}] (B1) -- (B2);
    \draw[middlearrow={<}] (B2) -- (B3);
    \draw[middlearrow={<}] (A1) -- (A2);
    \draw[middlearrow={<}] (A2) -- (A3);
    \draw[middlearrow={>}, dashed] (A1) -- (B1);
    \draw[middlearrow={>}] (B1) -- (A2);
    \draw[middlearrow={>}] (A2) -- (B2);
    \draw[middlearrow={>}] (B2) -- (A3);
    \draw[middlearrow={>}, dashed] (A3) -- (B3);

enter image description here


another proposition with use of tikz package ... with use of \usetikzlibrary{arrows.meta, decorations.markings, positioning}:

documentclass[tikz, margin=3mm]{standalone}
\usetikzlibrary{arrows.meta, decorations.markings, positioning}

node distance = 22mm and 11mm,
   dot/.style = {circle, fill=black, inner sep=0pt, minimum size=2mm,
                 node contents={}},
    ma/.style = {decoration={% middle arrows
                 mark= at position 0.5 with {\arrow{Straight Barb[length=3pt]}} ,
every edge/.append style = {ma, postaction={decorate}, semithick}
% from botom to top
% star coordinate
\coordinate             (a);
% nodes (ziga-zag
\node (a1)  [dot, label=below:$\alpha_1$,  right=of a];
\node (b1)  [dot, label=$\beta_{1}$,       above right=of a1]; 
\node (a2)  [dot, label=below:$\alpha_{2}$,below right=of b1];
\node (b2)  [dot, label=$\beta_{2}$,       above right=of a2]; 
\node (a3)  [dot, label=below:$\alpha_{3}$,below right=of b2];
\node (b3)  [dot, label=$\beta_{3}$,       above right=of a3];
% end coordinates
\coordinate (b) at (a |- b1);
% end coordinates
\coordinate[right=of b3,label=right:$\beta$]        (bb);
\coordinate[right=of b3 |- a3,label=right:$\alpha$] (aa); 
% continuation dashed lines
\draw[dashed] (a) -- (a1)   (a3) -- (aa)
              (b) -- (b1)   (b3) -- (bb);
% arrows
\draw[ma,dashed]        (a1) edge (b1)  (a3) edge (b3);
\draw   (b1) edge (a2)  (a2) edge (b2)  (b2) edge (a3) 
        (a3) edge (a2)  (a2) edge (a1) 
        (b3) edge (b2)  (b2) edge (b1);

![enter image description here


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