Rosencrantz and guildenstern are dead?

The Tradgedians in "Rosencrantz and Guildenstern are Dead" are the players from "Hamlet" who Hamlet has play the play "in which [he'll] catch the King." Basic, I know, but we have to start somewhere. Stoppard is using these players as a piece of Meta-Theatre. Keep in mind one of the central themes of R&G is Art versus Reality.