“…The effective action of gauge theory occasionally including massive hypermultiplets in the fundamental representation of the gauge group has been discussed in many view points, and accordingly, we have now much acquaintance with various properties of the prepotential and it's related materials, such as Picard-Fuchs equations for periods, 3,4,5,6,7 renormalization group like equation for prepotential, 8,9,10,11,12,13 relation to integrable systems, 14,15 appearance of WDVV equations, 16,17,18 flat coordinates 19,20 and so on.…”