I would like to know how to show an mapping or function is well defined
i think in generale we use that :
-$f$ is well defined mapping iff $( x\in E\implies f(x)\in F)$
in particular when mapping have quotion set such as :
$$f: \mathbb{Z}_2 \rightarrow \mathbb{Z}, \overline{x} \mapsto f(\overline{x}) $$ we use : $$\forall x,y,\ x=y\Rightarrow f(x)=f(y)$$
Am i right ? and "what is mathematical formulas for well-defined
for example :
by the way i read this https://en.wikipedia.org/wiki/Well-defined