“…It was Sato [93,94] and Segal and Wilson [96] who pioneered the connection between Fredholm Grassmannians and integrable systems. Recently there has also been a resurgence in this direction as well, see for example, Mulase [76], Dupré et al [36,37,38], Kasman [63,64], Hamanaka and Toda [59], Cafasso [18], Cafasso and Wu [19] and Arthamonov et al [7] (also see Beck et al [10,11,12] and Doikoi et al [31,32]). Related to this is the well-studied connection between the Korteweg-de Vries hierarchy, the intersection theory of Deligne-Mumford moduli space and the a string equation in two-dimensional gravity; see for example Witten [105,106] and Cafasso and Wu [19].…”