Glossary
UMA
Universal Market Access — an "optimistic" oracle that posts proposed answers and lets anyone challenge them within a window, with disputes resolved by token-holder vote.
UMA's optimistic oracle works by allowing anyone to assert a value on-chain along with a bond; if no one challenges within the liveness window, the value is accepted. Challenged assertions go to a DVM (Data Verification Mechanism) vote of UMA token holders, who resolve the dispute.
The model is well-suited to subjective or hard-to-aggregate data (election outcomes, "did event X happen"). Polymarket relies on UMA for market resolution; Across uses UMA for bridge settlement.