import type { PropFormula } from "../../models";
/**
 * Checks if disjunction introduction is applicable.
 *
 * Disjunction introduction allows us to infer a disjunction from any two formulas as disjuncts.
 *
 * @param formulas - An array of propositional formulas to check.
 * @returns `true` if there are exactly two formulas in the array, otherwise `false`.
 * @category Validators
 */
export declare function isDisjunctionIntroductionApplicable(formulas: PropFormula[]): boolean;