Function eq_ind

pub fn eq_ind<F: Field>(x: &[F], y: &[F]) -> F

Evaluates the equality indicator multilinear at a pair of coordinates.

This evaluates the 2n-variate multilinear polynomial

$$ \widetilde{eq}(X_0, \ldots, X_{n-1}, Y_0, \ldots, Y_{n-1}) = \prod_{i=0}^{n-1} X_i Y_i + (1 - X_i) (1 - Y_i) $$

In the special case of binary fields, the evaluation can be simplified to

See DP23, Section 2.1 for more information about the equality indicator polynomial.