LaTeX/Special Characters - Wikibooks, open books for an open world
LaTeX Math Symbols – The Garden at 13 Broom Acres
Accents used in Text
mathcal - Curly brackets and Big O notation - TeX - LaTeX Stack Exchange
Big O and related notations in LaTeX – texblog
TeX and Typography on X: "To write Erdős in LaTeX, use Erd\H{o}s. The mark over the o is not an umlaut but a double acute accent, a Hungarian variation on the umlaut.
How to denote Big O notation in LaTeX like O(n log n)?
amsmath - Big O notation - visual difference related to document configurations - TeX - LaTeX Stack Exchange