Users can make formulas, rewrite rules, and deduction rules immune or ancestor-immune to protect them from automatic normalization, both to enhance the performance of LP and to preserve particular forms for use in a proof. Users can also deactivate rewrite rules to prevent them from being applied automatically. The normalize and rewrite commands explicitly apply rewrite rules (whether or not active) to facts (whether or not immune).
Inactive deduction rules are not used for automatic deduction, and immune formulas and rewrite rules are not subject to automatic deduction. Users can also apply deduction rules explicitly, for example, to immune formulas.