import type { PropFormula } from "../../models";
/**
 * Checks if negation elimination is applicable to all given formulas.
 *
 * Negation elimination states that if we have a double negation, we can remove it.
 * This function verifies whether each formula in the array has exactly two negations at the top level.
 *
 * @param formulas - An array of propositional formulas to check.
 * @returns `true` if all formulas contain exactly two negations, otherwise `false`.
 * @category Validators
 */
export declare function isNegationEliminationApplicable(formulas: PropFormula[]): boolean;