Pushdown Automaton - Understanding The Computation Process

Understanding The Computation Process

The following illustrates how the above PDA computes on different input strings. The subscript from the step symbol is here omitted.

(a) Input string = 0011. There are various computations, depending on the moment the move from state to state is made. Only one of these is accepting.

(i) . The final state is accepting, but the input is not accepted this way as it has not been read.
(ii) . No further steps possible.
(iii) . Accepting computation: ends in accepting state, while complete input has been read.

(b) Input string = 00111. Again there are various computations. None of these is accepting.

(i) . The final state is accepting, but the input is not accepted this way as it has not been read.
(ii) . No further steps possible.
(iii) . The final state is accepting, but the input is not accepted this way as it has not been (completely) read.

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