prediction-markets

Prediction Markets

A module for creating, reporting, and disputing prediction markets.

Overview

Prediction markets are speculative markets that trade on future outcomes. While a prediction market is active, traders can permissionlessly trade on outcome assets. Complete set of outcome assets can be generated by exchanging base currency (ZTG) at a 1:1 exchange rate, meaning that 1 ZTG is used to generate 1 of each outcome asset of the market. A complete set of outcome assets (an equal amount of each outcome asset for a market), can be used to do the reverse exchange, being used to exchange 1:1 back to ZTG.

This pallet implements a two types of prediction markets:

• Categorical market - A market that can trade up to 8 different categories of outcomes. In the most simple case, when the outcomes are binary options (i.e. "YES" or "NO") the market has only two categories.
• Scalar markets - A market that trades Long or Short positions on a range of outcomes.

Interface

Dispatches

Public Dispatches

• buy_complete_set - Buys a complete set of outcome assets for a market.
• create_categorical_market - Creates a new categorical market.
• create_cpmm_market_and_deploy_assets - Creates a market using CPMM scoring rule, buys a complete set of the assets used and deploys the funds.
• deploy_swap_pool_for_market - Deploys a single "canonical" pool for a market.
• deploy_swap_pool_and_additional_liquidity - Deploys a single "canonical" pool for a market, buys a complete set of the assets used and deploys the funds as specified.
• dispute - Submits a disputed outcome for a market.
• redeem_shares - Redeems the winning shares for a market.
• report - Reports an outcome for a market.
• sell_complete_set - Sells a complete set of outcome assets for a market.
• start_global_dispute - Starts a global dispute for a market, when the MaxDisputes amount of disputes is reached.

Admin Dispatches

The administrative dispatches are used to perform admin functions on chain:

• admin_destroy_market - Destroys a market and all related assets, regardless of its state. Can only be called by the DestroyOrigin.
• admin_move_market_to_closed - Immediately moves a market that is an Active state to closed. Can only be called by CloseOrigin.
• admin_move_market_to_resolved - Immediately moves a market that is Reported or Disputed to resolved. Can only be called by ResolveOrigin.

The origins from which the admin functions are called (CloseOrigin, DestroyOrigin, ResolveOrigin) are mainly minimum vote proportions from the advisory committee, the on-chain governing body of Zeitgeist that is responsible for maintaining a list of high quality markets and slash low quality markets.

ApproveOrigin and RejectOrigin Dispatches

Users can also propose markets, which are subject to approval or rejection by the Advisory Committee. The ApproveOrigin calls the following dispatches:

• approve_market - Approves a Proposed market that is waiting approval from the Advisory Committee.

The RejectOrigin calls the following dispatches:

• reject_market - Rejects a Proposed market that is waiting approval from the Advisory Committee.