finite-automata,automata,turing-machines,automata-theory

You can use a stack. To begin with, suppose you took your Turing machine, and added to it another track. Clearly, it is is possible to use the additional track for the stack. However, a multitrack Turing machine is equivalent to a Turing machine, and there is a mechanical way...

finite-automata,automata,automata-theory

s -> Bx x -> Ay | By | Cy y -> Ay | By | Cy | A It is not too difficult to draw the finite automaton. The small letters are the states, the capital letters are the input symbols. State "s" is the start state. From there...

context-free-grammar,automata,automata-theory

Checking whether a grammar is ambiguous or not is an Undecidable problem, which means that there exists no algorithm which will correctly output Yes/No to this problem every time. The undecidablity is shown by showing that it is equivalen to Post Correspondence Problem, which is also undecidable....

finite-automata,automata,pda,pushdown-automaton,automata-theory

Of course, every state can be final in a deterministic pushdown automaton. Your approach seems correct to me. Depending on your definition on determinism it might be necessary to also add a transition that deals with the case where you read a 0 in state q_1 in order to have...