Infinity is a multi-LST liquidity pool (LP). Most LPs only have two assets (e.g. USDC-SOL). Some LPs, like a Curve stableswap pool, support three or four assets (e.g. USDC-USDT-DAI). Infinity supports all whitelisted LSTs (e.g. SOL-bSOL-bonkSOL-cgntSOL-compassSOL-driftSOL-…)
Infinity is the only liquidity pool able to support millions of different LSTs natively. Because all LSTs can be converted into a stake account, it is possible to calculate a fair price for every LST by looking at the SOL contained in the stake account. This lets Infinity support swaps between any two LSTs of any size without having to rely on any constant-product or stableswap invariant.
Infinity will have a target allocation of each LST that aims to maximise trading returns while providing a minimum for each LST. The pool maintains its target allocation by dynamically adjusting swap fees for each LST.
INF is itself an LST and so can be directly used by DeFi protocols. All LSTs will be able to share the liquidity of INF-USDC and INF-SOL, or route via INF to access the liquidity from any other LST pair.
There is no limit to the number of LSTs that Infinity can support — which explains the name.