@0g-brier/protocol

The Dynamic Pari-mutuel Market maths behind Brier, in TypeScript. A mirror of the Solidity library, pinned to it by vectors generated from the contracts themselves — a mirror is only worth having if something fails when it drifts.

npm i @0g-brier/protocol

import {dpm, WAD, networkFor} from "@0g-brier/protocol";

const q: readonly [bigint, bigint] = [1000n * WAD, 1200n * WAD]; // [NO, YES]

dpm.probability(q, 1); // 0.590… — P(YES)
dpm.price(q, 1);       // 0.768… — the marginal PRICE per share

Those are different numbers, and confusing them is the mistake this package exists to prevent. The implied probability is pᵢ²; the marginal price is pᵢ. A price shown with a % sign is a lie about the instrument.

A winning share pays 1/pᵢ, funded entirely by the pool — so every later buyer on your side dilutes you, including your own next order. dpm.costUp, sharesForSpend and quote size a trade against that.

Deployment manifests load through the ./node entry point:

import {loadDeployment} from "@0g-brier/protocol/node";
const {contracts} = loadDeployment(16661, "./deployments"); // 0G mainnet

MIT.