Like any AMM pool (Uniswap, Balancer, etc.), each Power Index has a corresponding ERC20 token, a share of all underlying tokens in the pool.
Generally, for each pool(index), we call this token
Power Index Pool Token or
PIPT, but for different indices, token name and symbol can be other, e.g., for
Yearn Ecosystem Token Index token name and symbol are
Yearn Ecosystem Token Index and
Users mint PIPT in two ways:
users provide liquidity to the pool simultaneously in all tokens in proportions determined by their weights using
joinPool(). We call this "Multi assets liquidity provision";
Users burn PIPT in two ways:
users remove liquidity from the pool simultaneously in all tokens in proportions determined by their weights using
Of course, anyone can buy any PIPT as an ERC20 token on the secondary market.