SolverTypes.GenericEqIncrSolverBaseA solver is something that can translate a system into a solution (hash-table). Incremental solver has data to be marshaled.
module S : ConstrSys.EqConstrSysThe hash-map that is the first component of solve xs vs is a local solution for interesting variables vs, reached from starting values xs. As a second component the solver returns data structures for incremental serialization.