Today, the computer program AlphaGo from Google won against the Go world champion Lee Sedol. I read that it won by resignation. If I understand correctly, it means that Lee realized he could not win and accepted his defeat without ending the game. My question is, by how many point AlphaGo would have won approximately if Lee had fought until the end?
The DeepMind channel on Youtube has a short review of each game by Michael Redmond 9P.
At the end of the summary for game 1, Michael estimates that black is slightly ahead on the board. When you factor in the 7.5 point komi, it means that the final score would have been around 5.5 in favor of AlphaGo.
AlphaGo does not attempt to maximize its points or its margin of victory. It tries to maximize its probability of winning.
You can download the game record (.sgf) file from this link and use an score estimator as in the KGS Goban (free), which will give you W+2.5 (including komi) and by looking at the screen we can see that AlphaGo could easily got additional points, so perhaps 5.5 as in the previous answer is the best estimate.