Cepheus is the first poker playing program that "essentially weakly solved" the game of heads-up limit Texas hold 'em. This was the first imperfect information game played competitively by humans to be essentially solved. It was developed by the Computer Poker Research Group (CPRG) at the University of Alberta and was introduced in January 2015 in a paper entitled "Heads-up limit hold'em poker is solved", published in Science by Michael Bowling, Neil Burch, Michael Johanson, and Oskari Tammelin.
Not who you're looking for? Others named Cepheus: constellation in the northern celestial hemisphere · lunar impact crater · set of mythological Greek characters