# Diagrams and xy-pic package

I want to reproduce the shape of the following diagram :

And the closest thing I could manage with the xy package was :

$$\xymatrix{ &B \ar[r] & H \ar[r] & B \ar[rd] \\ E'_{n+1} \ar[ru] \ar[r] & & E'_{n} \ar[r] & E_n \ar[r] & E_{n+1} }$$


which gives

Is it possible to do so with this package?

• It preferible to use $...$ instead of $$...$$ suggestion – Sebastiano Jan 2 at 20:22

Make a seven-column matrix:

\documentclass{article}
\usepackage{amsmath}

\usepackage[all,cmtip]{xy}

\begin{document}

$\xymatrix@C-1pc{ & B' \ar[rr]^{t_i} && H \ar[rr]^i && B \ar[dr]^{\tilde{v}} \\ E'_{n+1} \ar[ur]^{t_{\tilde{w}}} \ar[rr]_{t_{j_n}} && E'_n \ar[rr]_{\bar{u}} && E_n \ar[rr]_{j_n} && E_{n+1} }$

\end{document}


The instruction @C-1pc reduces the space between columns.

With the missing arrows:

\documentclass{article}
\usepackage{amsmath}

\usepackage[all,cmtip]{xy}

\begin{document}

$\xymatrix@C-1pc{ & B' \ar[rr]^{t_i} && H \ar[rr]^i \ar[dr]^v && B \ar[dr]^{\tilde{v}} \\ E'_{n+1} \ar[ur]^{t_{\tilde{w}}} \ar[rr]_{t_{j_n}} && E'_n \ar[rr]_{\bar{u}} \ar[ur]^{t_w} && E_n \ar[rr]_{j_n} && E_{n+1} }$

\end{document}


With tikz-cd:

\documentclass{article}
\usepackage{amsmath}

\usepackage{tikz-cd}

\begin{document}

$\begin{tikzcd}[column sep=small] & B' \arrow[rr,"t_i"] && H \arrow[rr,"i"] \arrow[dr,"v"] && B \arrow[dr,"\tilde{v}"] \\ E'_{n+1} \arrow[ur,"t_{\tilde{w}}"] \arrow[rr,"t_{j_n}"'] && E'_n \arrow[rr,"\bar{u}"'] \arrow[ur,"t_w"] && E_n \arrow[rr,"j_n"'] && E_{n+1} \end{tikzcd}$

\end{document}


Labels are by default typeset on the left of the arrow (think to rivers), but with "<label>"' (note the apostrophe) the label goes on the other side. Alternatively, precede the label with the keyword swap.

• Thank you so much for your complete a really clear answer! – Netchaiev Nov 28 '18 at 12:46