I need to do a graph similar to the one in the picture above but I don't know how to do the horizontal lines without the arrow, or the vertical arrow. The best I could do is the following:
\documentclass{amsart}
\usepackage{tikz}
\begin{document}
\begin{center}
\begin{tikzpicture}
\node (p1) at ( 0, 0) {};
\node (p2) at ( 1, -0.2) {i};
\node (p3) at ( 3,0) {};
\node (p4) at ( 0,1) {};
\node (p5) at ( 2,1.2) {n+j};
\node (p6) at ( 3,1) {};
\begin{scope}[every path/.style={->}]
\draw (p1) -- (p3);
\draw (p4) -- (p6);
\draw (p2) -- (p5);
\end{scope}
\end{tikzpicture}
\end{center}
\end{document}
Output
style={->}
. :)i
andn+j
in math mode? ($i$
and$n+j$
)