Does a PDA only move states when both the input symbol matches and the symbol on the top of the stack matches?
In other words, is it possible to have two different transitions that both take the same input character but pop different stack symbols?
For example if we have a state
Q0 with the two following transitions:
a, a -> b
a, b -> a
I know that a PDA will transition in regards to the input symbol but how does it handle the stack symbol that it is trying to pop?
For some reason I can not find the answer to this simple question for the life of me. I have searched and searched in my textbook and online.