pub fn two_wl_fingerprint(num_vars: usize, clauses: &[Vec<Lit>]) -> Vec<usize>Expand description
The label-independent 2-WL fingerprint: the sorted multiset of pair-color class sizes. Two formulas with different fingerprints are provably non-isomorphic (as colored variable structures) — the distinguishing power that separates, e.g., a 6-cycle from two triangles where 1-WL cannot.