Rule Resolution in Pega is the mechanism that selects the best rule to execute based on factors like class hierarchy, rule set availability, circumstance, and other criteria. It applies to rule types that can have multiple versions targeting different contexts, like Declare-OnChange, Declare-Constraints, Declare-Trigger. Rule-HTML-Property is a UI rule that defines how a property is displayed and is selected directly by its class and rule set - it does not participate in rule resolution.