There are three types of price in SynFutures contracts.
Fair price: SynFutures market trading price as implied by AMM inventories. The futures trader execute for a transaction which follows a Constant Product Formula model x*y=k.
Index price: Spot price of the trading pairs as supplied by Oracles. Currently we use Uniswap and Chainlink for index price.
Mark price: Price to determine whether a futures position should be liquidated and the settlement price at expiry. At TRADING state, it is defined as spot IndexPrice + MarkBasis, where the MarkBasis keeps the relationship between futures price and spot index stable by applying Exponential Moving Average (EMA) on past basis. While In the last hour of a futures contract, basis is assumed to be 0 and the MarkPrice will be the Time-Weighted Average Price (TWAP) of Spot Index to facilitate the price convergence to the spot and the eventual settlement.
For detailed calculation of the pricings, please check advanced topics.