Often only the existence of a dual isogeny is needed, but the construction is explicit as
where is the group of divisors of degree 0. To do this, we need maps given by where is the neutral point of and given by .
To see that , note that the original isogeny can be written as a composite
and that since is finite of degree , is multiplication by on .
|Date of creation||2013-03-22 12:52:58|
|Last modified on||2013-03-22 12:52:58|
|Last modified by||mathcam (2727)|