import type { PropFormula } from "../../../models";
/**
 * Applies negation elimination rule:
 * If ~(~A), then we can infer ~A.
 *
 * @param formulas An array of propositional formulas.
 * @returns {[PropFormula]} A tuple containing the inferred formula.
 * @throws {Error} if negation introduction rule is not applicable.
 */
export declare function negationElimination(formulas: PropFormula[]): [PropFormula];