How Does the Concept of “Fork Choice Rule” Apply in a PoS Environment?

The fork choice rule is the algorithm a node uses to determine which chain to follow when faced with two or more competing chains (a fork). In PoS, the rule is often based on which chain has the most "weight" (the largest amount of total staked capital attesting to it) or which chain has achieved finality.

This ensures network-wide consensus on the canonical chain.