Question

Many of you asked why we couldn't have two stacks for PDAs? Now here comes a problem for you. It is natural to add an extra stack to a PDA Say M is a two-stack PDA if M is exactly the same as a PDA but with two stacks. Each instruction (transition) in M is in the form of which means that if M is at state q and reading input symbol a with the M to state p, and replaces the tops b1 and b2 of the two stacks to γι and 72 respectively. Show (describe) that any Turing machine can be simulated by a two-stack PDA.

Answer 1