PartyB

Also referred to Solver Hedger MarketMaker

PartyB, Solvers, Hedgers, Counterparty or MarketMaker describe the same entity in Symmio, they describe the Executing party of a Trade contrarian to the requesting entity, which would be referred to as PartyA, Trader or User.

PartyB

PartyB is the TradFi term used to describe a counterparty in a Swap Agreement.

Counterparty: Definition, Types of Counterparties, and ExamplesInvestopedia

It was the first term we gave to counterparties in the Symmio ecosystem, a PartyA is the Trader that initiates the trade, a PartyB is the counterparty that accepts the trade. In Symmio PartyB is the counterparty which is declared as an Address on the Symmio core contract.

Solver

Solver is the established industry term for counterpartys in intent-based systems, PartyBs in Symmio can also be referred as Solver, it makes sense to especially refer to the onchain parts of a PartyB as "Solver", there could be Counterparties that exist as multiple entities, solvers that handle the onchain execution and MarketMakers or Hedgers that handle offchain liquidity. https://www.linkedin.com/pulse/realizing-user-centric-experiences-promise-intent-based-bao-ngoc-le/