Many mathematical models in the fields of physics, chemistry, biology and geology can be boiled down to the fixed solution problem of linear or nonlinear partial differential equations (PDE.)

The DNA molecules of the solution space are fixed on the solid carrier, and then we get the all solutions of the perfect matching problem by the biochemical actions.

The DNA molecules of the solution space are fixed on the solid carrier, and then get the all solutions of minimal vertex covering problem by the biochemical actions.