It is known that the maximum and minimum amount of time a clock signals rising and falling edges require to travel from a root of {HEAD ~ the subtree} to any sink receiving the clock signal via the subtree are not only functions of the characteristics of the conductors and active devices forming the subtree, but are also {TAIL ~ functions} of the clock signals rising and falling edge transition times at the subtree root 
It is known that the maximum and minimum amount of time a clock signals rising and falling edges require to travel from a root of { HEAD ~ the subtree } to any sink receiving the clock signal via the subtree are not only functions of the characteristics of the conductors and active devices forming the subtree , but are also { TAIL ~ functions } of the clock signals rising and falling edge transition times at the subtree root
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH