1 | initial version |

The polynomial `Phi`

can only be evaluated at two inputs (using the function call syntax). The method `roots`

is only available for single variable polynomials. Your `Phi(33,Y)`

is (in SageMath) still a multivariable polynomial (in which `X`

does not appear). To convert it to a single variable polynomial in `Y`

, use the `univariate_polynomial`

method:

```
sage: f = Phi.subs(X=33).univariate_polynomial(); f
Y^3 + 6150*Y^2 + 5541*Y + 1175
sage: f.parent()
Univariate Polynomial Ring in Y over Finite Field of size 8009
sage: f.roots()
[(898, 1)]
sage: f.roots(multiplicities=False)
[898]
```

Alternatively:

```
sage: R.ideal([Phi, X-33]).variety()
[{Y: 898, X: 33}]
```

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