Kernel of an isogeny
= Kernel of an isogeny
{title2=$E[\phi]$}
For an isogeny $\phi:E\to E'$, its kernel is denoted $E[\phi]$. In characteristic zero its cardinality equals $\deg\phi$.
= Kernel of an isogeny
{title2=$E[\phi]$}
For an isogeny $\phi:E\to E'$, its kernel is denoted $E[\phi]$. In characteristic zero its cardinality equals $\deg\phi$.