Dual isogeny
= Dual isogeny
{title2=$\widehat\phi$}
{wiki=Dual_isogeny}
The dual of an isogeny $\phi:E\to E'$ of degree $n$ is the unique isogeny $\widehat\phi:E'\to E$ satisfying
$$
\widehat\phi\phi=[n],\qquad \phi\widehat\phi=[n].
$$
= Dual isogeny
{title2=$\widehat\phi$}
{wiki=Dual_isogeny}
The dual of an isogeny $\phi:E\to E'$ of degree $n$ is the unique isogeny $\widehat\phi:E'\to E$ satisfying
$$
\widehat\phi\phi=[n],\qquad \phi\widehat\phi=[n].
$$