  We show that a given set of first class constraints becomes abelian if one
maps each constraint to the surface of other constraints. There is no
assumption that first class constraints satisfy a closed algebra. The explicit
form of the projection map is obtained at least for irreducible first class
constraints. Using this map we give a method to obtain gauge fixing conditions
such that the set of abelian first class constraints and gauge fixing
conditions satisfy the symplectic algebra.
