In propositional logic we have the DeMorgan's laws:
$$\lnot (p\lor q) \Leftrightarrow \lnot p\land \lnot q$$ $$\lnot (p\land q) \Leftrightarrow \lnot p\lor \lnot q$$
I would like to teach the laws of logic to my students, but changing the symbol $\Leftrightarrow$, because I don't want to confuse them with $\leftrightarrow$. Can I introduce =, instead of $\Leftrightarrow$? what is the default symbol of the logic equivalence used to researchers in this area?