latex step by step - Serbipunk/notes GitHub Wiki

best reference by now

https://www.math.uci.edu/~xiangwen/pdf/LaTeX-Math-Symbols.pdf

\widetilde{a}

symbols

https://oeis.org/wiki/List_of_LaTeX_mathematical_symbols

hollow letter

\mathbb{R}

\mathcal{L}

https://tex.stackexchange.com/questions/104274/real-number-symbol-utf-8-%E2%84%9D-in-xetex

argmin

\underset{x}{\mathrm{argmin}}

https://tex.stackexchange.com/questions/5223/command-for-argmin-or-argmax