Originally Posted by ryan1234

It was my understanding, correct me if I'm wrong, but max operating V-speeds have to do with high-dynamic pressure problems, like flutter, aileron reversal, divergence, etc.....as such they are a function of EAS - depending on the effect.

Because EAS decreases with altitude for a given mach number, sonic flow starts to predominate (so Mmo takes over) - because higher altitudes will have lower dynamic pressures (which makes Vmo less critical). In the end, like you said, Mach is a the ratio of true airspeed / speed of sound at that particular temperature.