TEN scenarios exist in the qualification process for Group A of the Barclays ATP World Tour Finals.
But it may take just a single factor for Team Great Britain to win the Davis Cup. The conversation was about arithmetic in considering Andy Murray's match tonight against Jo-Wilfried Tsonga. Suffice to say the vagaries of the group format mean Murray could win and go out, or lose and continue his participation.
The Davis Cup equation is simpler, according to Leon Smith, head of player development at the Lawn Tennis Association. "It is up to the players to step up and join Andy," he said. "The rankings don't lie and the gap between Andy and the British No.2 is not good enough by any stretch of the imagination." Murray is at No.3 and Josh Goodall, at 236, is the next best, with Jamie Baker a place lower.
"I am sure that if we had a No.2 player who was closer to being a top-100 player then that would appeal even more to our No.1 player to play. Then you really feel you do not just have a chance of doing well, but actually going on to challenge to win it," said Smith.
"We have one of the best players in the world, probably for the foreseeable future, and we have double players who are among the best in the world and are only going to get better. It's not unthinkable that if we got a second player we could go on to win this competition."
Smith said he had held "positive" talks with Murray over the player's participation in the home Davis Cup tie against Russia in April at a venue still to be decided.
The coach was similarly positive about Murray's contribution to British tennis and his hopes of reaching the knockout stages of the tour finals.
Baker and Oliver Golding will both travel to Miami to participate in the US Open champion's brutal training block.
"He is one of the best players in the world and we have great access to him," said Smith. "Jamie and Ollie will both be at training camp with him. How good is that for them? It spreads the word. Jamie can come back to the National Training Centre and tell the guys what he was doing with Andy, tell them how Andy gets up at 6am and runs miles and miles on South Beach until he throws up at the end - He's doing Bikram yoga, he's doing weights, he's playing three hours a day."
He added: "It is about changing our culture. Andy has shown how much work is needed."
More work awaits Murray tonight. Novak Djokovic, who has already won two matches in the group, plays Tomas Berdych, who has won one match, in the afternoon before Murray (one win) marches out to face Tsonga, who has been beaten in both of his contests.
Smith, who watched the Scot lose narrowly to the world No.1, said: "He has maintained his level throughout the year in what is a demanding schedule beyond all belief."
Murray has beaten the world No.8 six times in seven attempts, winning the last five in a run stretching back to 2009.
"Andy is very, very good at understanding how to tactically exploit an opponent," said Smith. "Against Tsonga, he has obviously worked out a couple of areas where he has the tools to exploit his opponent.
"It is a good match-up for Andy. Tsonga has a great serve, but Andy is a great returner so he negates that. Once they get into the points situation, Andy is very, very good at exploiting those areas that Jo could be weak in."
Murray knows Tsonga stands between him and a semi-final place that will keep him at the 02 over the weekend before he goes on his first holiday for two years, then heads off to Miami for training.
He intends to spend Christmas at home but is relishing that holiday in the sun in an unspecified destination.
"I'm happy to do that for a couple of days," he said of lying on the beach. "But then after that I do try to do some stuff. Because your body, when you do just lie around, stiffens up. Then when you do start practising, it takes time to get back into it. Your body hurts quite a lot as well when you take a week off doing absolutely nothing. So I do try and still do stuff when I'm on holiday."
But work beckons today. The permutations for qualification will be cut after Djokovic plays Berdych but Murray will not be deflected from his main purpose by calculating the arithmetic.
"You should be able to just play the match and try to win," he said.
Murray now faces the heat of battle before he seeks his place in the sun.