# How to align two columns in an equation next to each other with no space?

I want to align two columns in an equation next to each other with no space. I am using the following code.

\begin{equation*}
\begin{aligned}[b]
N(vw)=N(s_iuw)=N(s_i(uw))
& = N(s_i) & \Delta \; &  s_iN(uw)s_i \\
& = N(s_i) & \Delta \; & s_iN(u)s_i \; \Delta \; s_iuN(w)u^{-1}s_i \\
& = N(v)   & \Delta \; & s_iuN(w)(s_iu)^{-1} \\
& = N(v)   & \Delta \; & vN(w)v^{-1}.
\end{aligned}
\qedhere
\end{equation*}


but there's a space between the two columns as below.

How do I get rid of the space?

• See the alignedat env, note that it takes a mandatory argument which in this case would be 2 Mar 22, 2020 at 23:21
• Is \Delta to be considered as a binary operation symbol? Mar 22, 2020 at 23:50

Judging from all \; commands, your Delta should be considered as a binary operation symbol.

Use alignedat.

\documentclass{article}
\usepackage{amsmath,amsthm}

\newcommand{\bDelta}{\mathbin{\Delta}}

\begin{document}

\begin{proof}
\begin{equation*}
\begin{alignedat}[b]{2}
N(vw)=N(s_iuw)=N(s_i(uw))
& = N(s_i) && \bDelta s_iN(uw)s_i \\
& = N(s_i) && \bDelta s_iN(u)s_i \bDelta s_iuN(w)u^{-1}s_i \\
& = N(v)   && \bDelta s_iuN(w)(s_iu)^{-1} \\
& = N(v)   && \bDelta vN(w)v^{-1}.
\end{alignedat}\qedhere
\end{equation*}
\end{proof}

\end{document}


• heading shows 2 answers but there is only one answer -- going the virus way Mar 23, 2020 at 0:44
• @jsbibra there are two deleted answers Mar 23, 2020 at 9:49