Long equation in latex

Question

I am trying to write the following equation but overfull \hbox will appear after running LaTeX to get a pdf. Could you please help me to write it in a proper way. Many thanks.

$$
(v_{-n}\dots v_{-1} \otimes v_{0} \otimes v_{1}\dots v_{m}) \dashv
(w_{-p}\dots w_{-1} \otimes w_{0} \otimes w_{1} \dots w_{q})\\
&=v_{-n}\dotsv_{-1} \otimes v_{0} \otimes v_{1} \dots v_{m}w_{-p}\dots
w_{q}
$$.

Answer 1

I recommend you use the amsmath package and \[ … \] instead of $$, as described here, or choose any other amsmath environments. I chose multline* for an environment since your & alignment was aligning to nothing.

\documentclass[12pt,oneside,a4paper]{article}
\usepackage{amsmath,amssymb}
\begin{document}

\begin{multline*}
(v_{-n}\dots v_{-1} \otimes v_{0} \otimes v_{1}\dots v_{m}) \mathbin\dashv (w_{-p}\dots w_{-1} \otimes w_{0} \otimes w_{1} \dots w_{q})\\
    =v_{-n}\dots v_{-1} \otimes v_{0} \otimes v_{1} \dots v_{m}w_{-p}\dots w_{q}
    \end{multline*}

\end{document}

Please mind that you had many typos in the code. Also, as @egreg points out, \dashv needs to be prefixed with \mathbin to yield a binary operator, with proper spacing