# Calculating Groebner base with constants

I want to see what the Groebner base of an ideal is, but the polynomials generating it have some constants inside. Is there any way to do that with Sage?

```
var('a')
R.<x,y> = PolynomialRing(CC, 2, order='lex')
I = ideal(y^4*a, y^2*x - y*a - x, y - x*a)
B = I.groebner_basis()
B
```

This doesn't seem to work. `a`

is the constant. Also, this example is just a dummy, I want to know in general how to have constant coefficient in polynomials.

See https://ask.sagemath.org/question/666... especially " see more comments"