import type { Extended } from './isExtension.js';
export declare const $ADD: unique symbol;
export type $ADD = typeof $ADD;
export type ADD<VALUE> = Extended<{
    [$ADD]: VALUE;
}>;
export declare const $add: <VALUE>(value: VALUE) => ADD<VALUE>;
export declare const isAddition: (input: unknown) => input is {
    [$ADD]: unknown;
};