Gamma Structure

Source: https://docs.polymarket.com/developers/gamma-markets-api/gamma-structure

Gamma provides some organizational models. These include events, and markets. The most fundamental element is always markets and the other models simply provide additional organization.

Detail

1. Market

   1. Contains data related to a market that is traded on. Maps onto a pair of clob token ids, a market address, a question id and a condition id

2. Event

   1. Contains a set of markets
   2. Variants:
      1. Event with 1 market (i.e., resulting in an SMP)
      2. Event with 2 or more markets (i.e., resulting in an GMP)

Example

• [Event] Where will Barron Trump attend College?
  • [Market] Will Barron attend Georgetown?
  • [Market] Will Barron attend NYU?
  • [Market] Will Barron attend UPenn?
  • [Market] Will Barron attend Harvard?
  • [Market] Will Barron attend another college?

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Source: https://docs.polymarket.com/developers/gamma-markets-api/overview

All market data necessary for market resolution is available on-chain (ie ancillaryData in UMA 00 request), but Polymarket also provides a hosted service, Gamma, that indexes this data and provides additional market metadata (ie categorization, indexed volume, etc). This service is made available through a REST API. For public users, this resource read only and can be used to fetch useful information about markets for things like non-profit research projects, alternative trading interfaces, automated trading systems etc.

Endpoint

https://gamma-api.polymarket.com

Overview

Source: https://docs.polymarket.com/developers/neg-risk/overview

Certain events which meet the criteria of being "winner-take-all" may be deployed as "negative risk" events/markets. The Gamma API includes a boolean field on events, negRisk, which indicates whether the event is negative risk.

Negative risk allows for increased capital efficiency by relating all markets within events via a convert action. More explicitly, a NO share in any market can be converted into 1 YES share in all other markets. Converts can be exercised via the Negative Adapter. You can read more about negative risk here.

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