Consider a vector that is made up of N times the same element, stacked next to each other. I am having a hard time coming up with an elegant mathematical notation for indicating the repetitiveness of the elements, and the how often they repeat.
The best I could come up with is:
\documentclass{article}
\usepackage{mathtools}
\begin{document}
\[
\underbrace{%
\begin{pmatrix}
\Delta t \mathbf{a}_b & \Delta t \mathbf{a}_b & \cdots & \Delta t
\mathbf{a}_b
\end{pmatrix}%
}_{N \times (\Delta t \mathbf{a}_b)}
\]
\end{document}
Can you propose a way to make this clearer in LaTeX?
\mathbf{a}_b
represent?