How does DAGKNIGHT select a block's chain predecessor?

DAGKNIGHT picks each block's chain predecessor by choosing whichever candidate minimizes that block's rank. In Kaspa's blockDAG, many blocks can exist at the same level, which creates conflicts about which one belongs on the main chain. DAGKNIGHT resolves those conflicts through a hierarchical process — each block evaluates its options and selects the predecessor that produces the lowest rank, giving the whole network one consistent, objective rule to follow. For a beginner, this matters because it means no human decision-maker or majority vote is needed to break ties: the rank-minimization rule does it automatically and uniformly across every node.