# Equivalent to Singular's minpoly?

Hello everyone

In Singular, one can define a ring such as

```
ring r = (0,i),(x,y),dp;
minpoly = i2+1;
```

in order to specify that the parameter *i* verifies *i²+1=0*. Can I do this, or is it at all needed to work with *Q(i)*, in Sage?

As of now, I have defined a ring

```
K.<x,y,I>=QQ[]
```

but I don't know if defining *I* as a parameter of the ring in Sage is needed, neither how could I define the minimal polynomial for *K*.

Thank you.

**Edit:** I discovered I can simplify each polynomial using `.mod(I^2+1)`

but I guess there has to be a more general solution that applies this to the ring itself.