Google's AlphaGo defeats Go grandmaster Lee Sedol in final match (4)

South Korean professional Go player Lee Sedol (C) attends a press conference after finishing the final match of the Google DeepMind Challenge Match against Google's artificial intelligence program, AlphaGo, in Seoul, South Korea, March 15, 2016. Google's Go-playing computer program again defeated its human opponent in a final match on Tuesday that sealed its 4-1 victory. (Xinhua/Yao Qilin)