Thus like prior art prior clock subtree models, a subtree model in accordance with the invention depicts the maximum and minimum delays between the root of a subtree and {HEAD ~ the sinks} connected to {TAIL ~ the subtree} as functions of the transition times of the rising and falling edges of the clock signal as it arrives at the root of the subtree 
Thus like prior art prior clock subtree models , a subtree model in accordance with the invention depicts the maximum and minimum delays between the root of a subtree and { HEAD ~ the sinks } connected to { TAIL ~ the subtree } as functions of the transition times of the rising and falling edges of the clock signal as it arrives at the root of the subtree
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