Three user types interact with Notional liquidity pools: lenders, borrowers, and liquidity providers. Lenders deposit Dai into the pool and receive fDai (a promise to receive a fixed amount of Dai at a future date). Borrowers take Dai from the pool and deposit fDai (a promise to pay a fixed amount of Dai at a future date). The liquidity provider adds Dai and Dec 1 2020 fDai into the pool which can be lent or borrowed by either party.