Prescribing symmetric scalar curvature onS 2

The problem of prescribing scalar curvature in S2 is discussed, and the solvability of the equation-Δu + 2 - Reu = 0on S2,is given, where R ∈ C0 (S2).It is known that there are some obstructions. Some new results are given by seeking a solution of the minimax type. For example, supposing that R is Gsymmetric and is constant on the set of fixed points on S2 under G (where Gis a subgroup of O(3)), itis proved that the equation is solvable if and only if Ris positive somewhere.