%%
%% The LaTeX Companion, 3ed
%%
%% Example 11-5-1 on page II-181 in "Ellipsis and other kinds of \protect \ldots  ".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{165.0pt}

%StartShownPreambleCommands
\usepackage{amsmath}
%StopShownPreambleCommands

\begin{document}
A series $H_1, H_2, \dots, H_n$, a sum
$H_1 + H_2 + \dots + H_n$, an orthogonal product
$H_1 \times H_2 \times \dots \times H_n$.
\end{document}