/**
 * Validates a REGON (Polish National Business Registry Number) string.
 * The function checks for 9- or 14-digit formats and calculates a checksum according to
 * REGON requirements. Any dashes or whitespace are ignored.
 *
 * @param {string} regon - The REGON number as a string, which may include dashes or whitespace.
 * @returns {boolean} `true` if the REGON is valid; `false` otherwise.
 */
export declare function isRegonValid(regon: string): boolean;
/**
 * Validates a REGON (Polish National Business Registry Number) string.
 * The function checks for 9- or 14-digit formats and calculates a checksum according to
 * REGON requirements. Any dashes or whitespace are ignored.
 *
 * @param {string} regon - The REGON number as a string, which may include dashes or whitespace.
 * @returns {boolean} `true` if the REGON is invalid; `false` otherwise.
 */
export declare const isRegonInvalid: (regon: string) => boolean;