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Using Zeitgeist Markets

Assets on Zeitgeist​

The ZTG Token and Other Currencies​

The native token on Zeitgeist is ZTG. On the Battery Station test network, this token is known as ZBS, but in SDK and CLI commands, and on this page, both ZTG and ZBS are called ZTG.

ZTG may be used as collateral (or base asset) in prediction markets. This means it's used as liquidity and for placing bets (like USD in the examples of the previous chapters); outcome asset tokens will not redeem for $1 when a market is resolved, but for 1 ZTG instead, and trading fees will be paid in ZTG. Other select foreign assets can be used as collateral as well.

Other uses of ZTG include governance, staking for dispute resolution (particularly in the Decentralized Court) and collator selection, and bonding for various on-chain actions, most importantly market creation. These actions require ZTG and ZTG only. Details follow below.

The total supply of ZTG at genesis was 100M. Each ZTG equal 1010=10, ⁣000, ⁣000, ⁣00010^{10} = 10,\!000,\!000,\!000 Pennocks, the smallest unit of currency on Zeitgeist. Whenever amounts of ZTG are specified in the SDK or polkadot-js, they are specified in Pennocks.

Outcome Asset Tokens​

Recall that outcome asset tokens (or outcome tokens for short) represent the possible outcomes of a future event. For example the prediction market "James Webb Space Telescope (JWST) launches on December 18" might have two outcome tokens, "Yes" and "No". A market on the winner of the Kentucky Derby would have an outcome token for each horse.

Liquidity Shares​

Trading on Zeitgeist is facilitated by liquidity pools. Those who wish to provide liquidity to these pools may join the pool with assets and mint liquidity pool shares, which represent their total share in the pool's liquidity. For example, if a pool's liquidity shares have a total issuance of 100 and Alice owns 10 liquidity pool shares, her share of the pool is 10%.

Once they have transferred the assets into the pool, the liquidity providers no longer control those assets, but will receive fees when others swap them with their own assets (usually ZTG) to compensate for the risk of being left holding the losing outcome tokens (see Resolving Markets and Redeeming Tokens).

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As liquidity provider for a prediction market, you are essentially betting against the informants' ability to predict future outcomes.

Anyone who owns liquidity pool shares may exit the pool and receive back their share of the pool's assets.

Zeitgeist Markets​

A prediction market on Zeitgeist is created using the create_market extrinsic. The market requires the following data...

  • The market type is either categorical or scalar. See prediction markets for details.

  • The creation type determines if the market is permissionless or advised. See [Creation Type] for details.

  • The oracle is a Zeitgeist address which is responsible for reporting the outcome, and deposits the oracle bond. This amount is paid in ZTG and is only returned to the market creator if the oracle has faithfully reported the market's outcome. If the oracle has failed to do so, the stake is slashed. See [disputes] for details.

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    The market creator can specify any address as oracle, but also provides the stake for the oracle. If the market creator specifies an unwitting oracle (by mistake or with malicious intent), the market creator will most likely lose their stake and the oracle will go unpunished.

  • The dispute mechanism is used to resolve disputes between users. See [disputes] for details.

  • The scoring rule determines the automatic market maker that the market's pools use. There's currently only one scoring rule available on Zeitgeist.

  • The period determines when a market opens and closes and is specified either in blocks or using UNIX timestamps (in milliseconds since epoch). The Zeitgeist application allows users to comfortably set the period using human-readable dates.

  • The grace period (may be zero) specified the number of blocks after the market has closed during which all activity on the market is halted. This allows us to stop trading without immediately allowing the oracle to hand in a report.

The curret status of a market is described by the status field. The market's initial status depends on the creation type. These phases are described in detail in the upcoming sections, but we provide a simple overview at this point.

After their period has ended, all markets are first closed and then enter the second stage of their lifecycle where they undergo a grace period, if configured. During this grace period, all trading and market activity is suspended, allowing for a cooldown before the resolution process begins. Following this, the designated oracle is required to report the outcome of the market. This reported outcome is crucial, as it is the basis for the settlement of bets and trades that occurred within the market.

However, this outcome is not necessarily final. There is an opportunity for disputes if participants believe the oracle's report is inaccurate or biased. The specific details of this dispute process are outlined in another section, focusing on the mechanics and timelines for raising and resolving disputes.

Once the dispute period has elapsed without any successful challenges, or after any disputes have been conclusively resolved, the market reaches its final resolution stage. At this point, the outcome as reported by the oracle or as determined through the dispute resolution process is considered final. Participants can then redeem their outcome tokens based on this final result, effectively settling all positions taken in the market.

Creation Type: Permissionless & Advised Markets​

The Zeitgeist network allows the permissionless creation of markets. Anyone can create a new market, provided they place a validity bond in ZTG. The purpose of the bond is to ensure that the market obeys the rules put in place by the Zeitgeist team. It is returned to the market creator after the market is resolved. A permissionless market that violates the market creation rules may be removed from the app without warning.

If the user does not wish to place the validity bond, they may instead create the market as advised and only place a smaller advisory bond. The Advisory Committee then decides if the market is valid. Until this decision is made, no liquidity pool may be deployed for the market and no complete sets may be bought or sold.

If the market is deemed valid according to the market creation rules, the advisory bond is returned to the creator and liquidity pools may be deployed. If, on the other hand, the market violated the rules or is invalid, the advisory bond is slashed or the user is asked to change the market before it is approved. Should, for any reason, the Advisory Committee not reach a decision until the market ends, the advisory bond and oracle bond are both returned to the creator.

Market Lifecycle​

The market opens when the starting block/timestamp is reached. If a liquidity pool is deployed for the market during market hours or before, users can swap assets and may provide liquidity to the pool.

The market closes when the ending block/timestamp is reached. This means that swapping assets and providing liquidity is no longer allowed, but users are allowed to remove their liquidity now that it is no longer used.

The oracle of the market is expected to submit which outcome actually occurred within a fixed frame of time, the reporting period. If the oracle fails to submit the report in time, the market creators stake will be slashed, and any address will be able to submit a report as an outsider.

Once the report is submitted, the status of the market changes from closed to reported.

Disputes​

When a report is submitted (by the oracle or an outsider), the market is not resolved for a certain window of time called the dispute period. When a participant believes the outcome reported by the oracle is incorrect, they have the option to initiate a dispute. This process starts with the deposit of a bond in ZTG, serving as a guarantee of the disputant's conviction in their claim. The dispute mechanism is modular, allowing for the implementation of various approaches to handle these disagreements.

Upon the initiation of a dispute, the market enters a special state where the reported outcome is effectively put on hold. The dispute mechanism, as defined in the market's rules, then takes over. This may involve additional rounds of voting, expert arbitration, or other methods to reassess the reported outcome.

If the dispute is resolved in favor of the disputant, their bond is returned, and the market outcome is adjusted accordingly. However, if the dispute is deemed unjustified, the bond is forfeited. This system ensures that disputes are raised only when there are genuine concerns about the market's outcome, maintaining the integrity and reliability of the market. More on that in the bonds section of the Using Zeitgeist Markets page.

Throughout this process, the market’s participants are kept informed, and the mechanisms ensure transparency and fairness, critical for maintaining trust in the market's operations and outcomes.

The default dispute mechanism used on Zeitgeist's app is the Decentralized Court. The other option that's currently available is the authorized mechanism, which delegates the decision over the dispute to the Advisory Committee.

Resolving Markets and Redeeming Tokens​

Once the window for disputes is closed, the market is resolved to the last reported outcome. All outcome tokens except for the winning outcome token are immediately burned. Traders who hold winning tokens can now redeem them for 1 ZTG apiece by signing a transaction. There is no time limit for redeeming winning outcome tokens.

For example, Alice holds 3 "Yes" and Bob holds 5 "No". If the market resolves to "No", then Alice's 3 "Yes" are burned and she is left with nothing, while Bob can redeem his 5 "No" for 5 ZTG from the prize pool.

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Redeeming tokens is different from selling tokens. Tokens cannot be traded after market close, but they can be redeemed for one unit of collateral each once the market is resolved.

Furthermore, as soon as the market is resolved, those who staked ZTG in a dispute for the token which the market eventually resolved to receive their stakes tokens back, while the stake of those who staked for other tokens are slashed.

Bonds​

There are four types of bonds utilized by prediction markets on Zeitgeist: creation, oracle, outsider and dispute bonds. Bonds are deemed settled when they are entirely unreserved or slashed.

  • The creation bond is reserved by the market creator at the time of market creation. Its size varies depending on whether the market's creation type is advised or permissionless, with the latter requiring a larger amount. If the market is advised, the creation bond is unreserved upon market approval or if the market period expires without receiving either approval or rejection. If the market is rejected, a portion of the bond is slashed, and the remaining part is unreserved. The specific portion to be slashed is determined by the AdvisoryBondSlashPercentage parameter. Conversely, if the market is created permissionlessly, the creation bond is unreserved upon the market's resolution. Regardless of the scenario, the creation bond serves to ensure the market creator's appropriate conduct.

  • The oracle bond is reserved by the market creator during market creation. It is unreserved upon the market's resolution if the oracle provided an honest report, confirmed as true by dispute or undisputed. If the oracle failed to provide a report or if it submitted a false report that was later disputed, the bond is transferred to the disputant or the outsider, resp. (see below).

  • The outsider bond is reserved by a user, referred to as the outsider, if they submit a report after the oracle failed to do so within the report period deadline. The outsider bond's settlement process mirrors that of the oracle bond. If the outsider's report was honest, the bond is returned, and the outsider also receives the oracle bond as a reward. If the outsider's report is later found to be false through a dispute, the bond is transferred to the disputant.

  • The dispute bond is reserved by a user, the disputant, upon submitting a dispute. If the dispute is justified and the original report is proven false, the dispute bond is unreserved, and the disputant is rewarded with the oracle and the outsider bond if available. If the dispute is unjustified, the bond is slashed.

Advanced Topics​

The Prize Pool​

On every market, outcome tokens may be minted in complete sets by users while the market is open (exactly one of each outcome token from the market) at the exact price of one unit of the market's base asset (see the ztg token and other currencies). The collateral paid for the mint is placed in the market's prize pool. All outcome tokens are created by minting them in this fashion. Complete sets may also be destroyed. For every complete set destroyed the user receives one unit of collateral back from the prize pool.

When a market is created, the prize pool is empty, and the balance of the prize pool cannot be changed except by minting and burning complete sets. These rules guarantee the prize pool contains exactly one unit of the base asset for every complete set of outcome tokens in circulation. This way the winning outcome token is backed 1:1 in collateral.

The prize pool should not be confused with the market's liquidity pool, which is described further below.

For example, Alice has 3.7 ZTG in her wallet. She mints 3.5 complete sets for the James Webb Space Telescope market, pays 3.5 ZTG (which goes into the prize pool of the JWST market) plus transaction fees, and receives 3.5 "Yes" and 3.5 "No".

Bob, on the other hand, has 2.1 "Yes" and 3.4 "No" tokens. He decides to destroy 2.1 complete sets (leaving him with only 1.3 "No") and receive 2.1 ZTG back from the prize pool. Note that Bob could not have destroyed any more complete sets, as he owns no more "Yes".

The Liquidity Pool​

Zeitgeist supports a constant function market maker called DLMSR, which is based on Robin Hanson's DLMSR, a variation on the basic x⋅y=constx \cdot y = \mathrm{const} formula.

By default, a new market has no liquidity pool. Instead, the pool must either be deployed by the market creator, or by some external liquidity provider. After the pool is created, others may join the liquidity pool by providing additional liquidity. For details on the function of the liquidity pool, see https://github.com/zeitgeistpm/zeitgeist/blob/main/zrml/neo-swaps/README.md.

Note that this means that trading can only happen when the liquidity pool is sufficiently deep. If the pool is too shallow, some trades may be impossible (Alice cannot buy 150 "Yes" from the pool above) or may suffer from excessive slippage (buying 50 "Yes" from the pool above will most certainly cost more than 25 ZTG).

Further reading​

1 Abraham Othman, Tuomas Sandholm, David M. Pennock, Daniel M. Reeves, A practical liquidity-sensitive automated market maker, ACM Transactions on Economics and Computation 1(3), pp. 377-386 (2010)