pub trait Column<F: FftField> {
// Required methods
fn domain(&self) -> GeneralEvaluationDomain<F>;
fn domain_4x(&self) -> GeneralEvaluationDomain<F>;
fn as_poly(&self) -> &DensePolynomial<F>;
// Provided methods
fn size(&self) -> usize { ... }
fn evaluate(&self, z: &F) -> F { ... }
}