• is the start state
• , is the initial stack symbol, and
• , is the final or accept states.

Explanation of the transition function, :

If, for any , . This means intitutively that whenever the PDA is in state q reading input symbol a and z on top of the stack, it can nondeterministically for any i,

• go to state
• pop z off the stack
• push onto the stack (where ) (The usual convention is that if , then will be at the top and at the bottom.)
• move read head right one cell past the current symbol a.