# Is computing dual isogenies broken?

Hi all,

I am trying to find duals of elliptic curve isogenies. I am following the example in the official documentation in the "Elliptic curves" section:

```
sage: k = GF(11)
sage: E = EllipticCurve(k,[1,1])
sage: Q = E(6,5)
sage: phi = E.isogeny(Q)
sage: phi.dual()
```

and I get the error

```
NotImplementedError: currently no algorithms for computing the Weierstrass p-function for that characteristic / precision pair is implemented. Lower the precision below char(k) - 2
```

Is there something I am doing wrong or is there indeed a bug? The problem manifests itself both wihs Sage7 and Sage8, on Linux and macOS and on SageCell.

Best, Jan