Constraints on Non-Holomorphic correction in N=2 superspace

We study quantum corrections on four derivative term of vector multiplets in ${\cal{N}}=2$ supersymmetric Yang-Mills theory. We first show splitting of quantum correction on gauge neutral hypermultiplets from U(1) vector multiplets at four derivative order. We then revisit the non-renormalization theorem given by N. Seiberg and M. Dine and show the non-renormalization theorem in mixed (coulomb plus Higgs) branch even though gauge neutral hypermultiplet develops the vacuum expectation value.