The AI, called Pluribus, defeated poker professional Darren Elias, who holds the record for most World Poker Tour titles, and Chris "Jesus" Ferguson, winner of six World Series of Poker events. Each pro separately played 5,000 hands of poker against five copies of Pluribus. In another experiment involving 13 pros, all of whom have won more than $1 million playing poker, Pluribus played five pros at a time for a total of 10,000 hands and again emerged victorious. "Pluribus achieved superhuman performance at multi-player poker, which is a recognized milestone in artificial intelligence and in game theory that has been open for decades," said Tuomas Sandholm, Angel Jordan Professor of Computer Science, who developed Pluribus with Noam Brown, who is finishing his Ph.D. in Carnegie Mellon's Computer Science Department as a research scientist at Facebook AI. "Thus far, superhuman AI milestones in strategic reasoning have been limited to two-party competition. The ability to beat five other players in such a complicated game opens up new opportunities to use AI to solve a wide variety of real-world problems."

"In regular poker, to force betting, each person puts in an ante," Palansky said. "We've changed some tournaments where one person essentially pays everyone's ante at once. So, when you are in a particular spot at the table, you pay everyone's ante and the rest of the time you don't pay any ante at all. If the ante is a chip value of 100, that person may put in 900 for all nine players.

Participants in this year's edition of the poker extravaganza will see two changes: no firm "shot clock" and the return of the tradition of crowning the tournament's main event champion in July. Buy-ins for the 74-event tournament, which runs through July 22 at the Rio All-Suite Hotel and Casino, range from $333 to $111,111.

The 47th annual World Series of Poker starts Tuesday at the Rio All-Suite Hotel and Casino. Among the 69 events is the tournament's Main Event, which begins July 9. It runs through July 18, when a final table of no-limit Texas Hold'Em players emerges. The final nine competitors will return to play at the Main Event championship Oct. 30 to Nov. 1. Pennsylvania poker pro Joe McKeehen won the gold bracelet last year, and a 7.68 million top prize. Organizers said the 2015 tournament had record-breaking attendance, including 103,512 entries and over 210 million in prize money.