Every YES and NO pair on Polymarket can be created or redeemed for exactly $1 on-chain (the Conditional Token Framework, or CTF). When the YES and NO sell prices add up to LESS than $1, you mint a fresh $1 pair for collateral and sell both halves on the order book for more than $1. When they add up to MORE than $1, you buy both cheap and redeem the pair for a clean $1. The edge is the gap between the fixed $1 on-chain value and the live order-book prices, after gas.
Markets on Polymarket where split/merge redemption arbitrage (ctf) is the natural play:
