Yeah Tina I guess technically you are correct. "PONG" was somewhat different from what Ralph invented. Alcorn did improve the game which is also true. But still... you have to give credit to Ralph for the whole idea. Heck even Alcorn gives the credit to Ralph and not Nolan for the original idea, "And Nolan got the idea from that, but it's like the movie The Producers, because he figured we'd rip off the idea for a game, but so what? It's no good, we're not going to sell it, we'll throw it away, so what harm is there, right? So, it didn't work out that way… they sent us a letter." - http://retro.ign.com/articles/858/858351p1.html
... and lets not forget the fact that Atari settled the infringement lawsuit with Magnavox and became a licensee...
Ralph's own words, "That lawsuit and others that followed it were largely about the interaction between manually-controlled and machine-controlled symbols on screen, like the paddles and the ball in a ping-pong game. Atari’s PONG game – which in any event came about because Atari’s President, Nolan Bushnell, had played an Odyssey ping-pong game at a Magnavox dealership demo in May of 1972 - infringed that technology and so did all of Atari’s competitors who copied the Pong game within months of it first appearance." - http://www.ralphbaer.com/how_video_games.htm
http://www.youtube.com/watch?v=1LsRGUODHlQ -- brown box ping pong
http://www.youtube.com/watch?v=LPkUvfL8T1I -- Atari pong
But I don't want to minimize at all what Nolan did for video games... the guy was definately a pioneer and did a ton of amazing things!