“…Indeed, Keolian et al (1981) showed the appearance of capillary waves in shallow water at subharmonic frequencies with other ratios of f=i, where i ¼ 2, 4, 12, 14, 16, 18, 20, 22, 24, 28, and 35. This, and more complex wave patterns [see, e.g., Binks and van de Water (1997)], is made possible, as shown by Chen and Viñals (1997), by the interaction of triad (three-wave) resonant interactions of the waves on the free surface that does not rely on the quadratic nonlinearity presumed by the weakly nonlinear form that results in the Mathieu equation form. Beyond discrete modes of capillary waves, the appearance of turbulent cascades in the wave interaction for larger systems where gravity is relevant has been shown to exist by .…”