import { type Fairness, type Spec, type World } from "../spec/index.ts";
import type { FairId } from "./liveness.ts";
import type { Choice } from "./steps.ts";
/**
 * A step's fairness (RFD0006): its identity, the same wherever it is possible, and how fair it
 * is. Deliveries, timers and guards are weakly fair unless their transition says otherwise;
 * actions are never fair.
 */
export declare function fairness(spec: Spec, world: World, choice: Choice): {
    id: FairId;
    kind: Fairness;
} | undefined;
/** The fair steps possible in a world, among its options, by identity. */
export declare function fairStepsIn(spec: Spec, world: World, options: Choice[]): Map<FairId, Fairness>;