Why is the compiler showing undefined control sequence for the below code: Note that I have already given the preamble of \usepackage{amsmath}
A Hoheisel Algebra is a core structure with $R=\mathbb{C}\ \ S=\mathbb{R}$, $A$ a commutative algebra, $B$ finite with $\beta_{iiH0}\in\mathbb{R}_{\ge0}\forall i\in I$.
Any hints? Thanks beforehand.
\documentclass{...}and ending with\end{document}. The exact error message would be helpful too: the console output has a line break at the undefined sequence. – campa Mar 21 '18 at 13:43amssymb(oramsfonts)? Otherwise no\mathbb... – campa Mar 21 '18 at 13:44