FYI, the Markman process does not "validate" patents. It simply determines as a legal matter what a contested claim term means. Even the PTO cannot "validate" an issued patent--it can only determine if there is enough evidence to invalidate it. If a patent is not invalidated (e.g., during reexamination) that does not mean it is valid. It just means that, for the time being, invalidity has not been proven. That does not mean someone else can't come along later with better prior art and prove the patent to be invalid, even though it's already been tried. Could be in court or in another reexamination.
IMO. GLTA