I am using WinEdt 6 for compiling my TeX documents. I am getting an error with contains the line $\mathbb{Z}$ showing that it is undefined control sequence. How should I rectify it? Should I include any math packages or something. I am a beginner in using TeX.
[Tex/LaTex] \mathbb{Z} yields undefined control sequence error
errorsmath-modesymbols
Related Solutions
You need to include \usepackage{amsmath}. The MWE below produces:
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{equation}
\left\|x\left[t\right]-\textbf{1} F(X)\right\|^2 = \sum_{i = 1}^{n} \lambda_i^2t \lvert x \left[ 0 \right] \rvert^2
\end{equation}
\end{document}
I wouldn't use \limits in this case since it'll end up placing the lower and upper limits of the sequence below and above the right-hand curly brace -- probably not what you intended.
If you write \{h_{n}\}_{0}^{\infty}$ (see the middle example below, labelled "not awful"), the upper and lower limits may look like they're too close to each other, especially in text-style math mode. One way to fix this is to encase the closing curly brace, \}, in a pair of braces to change its status from "math-close" to "math-ordinary"; doing so will loosen the spacing quite a bit.
It may be best, though, to define a custom macro called, say, \seqwlimits to standardize the task at hand and to assure adequate vertical separation of the upper and lower limits.
\documentclass{article}
\newcommand\seqwlimits[3]{\{#1\}_{\mathstrut#2}^{\mathstrut#3}}
\begin{document}
\begin{tabular}{ll}
huh?? & ${\{h_{n}\}}\limits_{0}^{\infty}$\\[2ex]
awful & $\{h_{n}\}\limits_{0}^{\infty}$\\[2ex]
not awful& $\{h_{n}\}_{0}^{\infty}$\\[2ex]
better & $\{h_{n}{\}}_{0}^{\infty}$\\[2ex] % note the extra { and }
best & $\seqwlimits{h_n}{0}{\infty}$\\
\end{tabular}
\end{document}
Best Answer
Load the
amsfontspackage, this provides that command:Optionally you could load
amssymb, as this in turn loadsamsfonts.For reference, the Comprehensive LaTeX Symbol List has also a table of mathematical alphabets, and the packages required for using them. In the current version (dated 25 June 2020) of the document, it is table 316 with the caption Math Alphabets. It is the final table in chapter 3 Mathematical symbols.