Denisovich said:
To summarize: if Nadal wins two matches, its a done deal. Nadal gets ye no 1. If Nadal wins one match, Novak needs to win everything (not sure if two live rubbers are necessary then though). If Nadal loses all his matches, there is a little bit of space left for Novak, but I haven't done those calculations.
Nadal's current lead over Djokovic is 1420. Djokovic can get a maximum of 1500 in
WTF and an additional 225 in DC for a possible total of 1725.
1. If Nadal wins two matches, it is a done deal. Nadal is YE#1.
2. If Nadal wins one match, Djokovic needs to win WTF and two live rubbers at DC Finals
to become YE #1. If he does anything less, then Nadal is YE#1.
3. If Nadal wins zero matches, Djokovic can become YE #1 by just winning WTF.
He does not need to win even a single match at DC. Also, if he does not win
WTF, he will not be #1 no matter what happens in DC.