PDA-Acceptance By Final State - Free MCQ Practice Test with solutions,

A push down automata uses a stack to carry out its operations. They are more capable than the finite automatons but less than the turing model.

 The term pushdown refers to the fact that the elements are pushed down in the stack and as per the LIFO principle, the operation is always performed on the top element of the stack.

In computational theory, a nested stack automaton is a finite automaton which makes use of stack containing data which can be additional stacks.

The 10-tuple can be stated as: NSA= ‹Q,Σ,Γ,δ,q0,Z0,F,[,],]›.

 Push down automata is for Context free languages and they are termed as Type 2 languages according to Chomsky hierarchy.

: NSPACE or non deterministic space is the computational resource describing the memory space for a non deterministic turing machine.

This class of automata can recognize a set of context free languages like {anbn|n belongs to N}

Push and pop are the operations we perform to operate a stack. A stack follows the LIFO principle, which states its rule as: Last In First Out.
Explanation: When we reach the acceptance state and find the stack to be empty, we say, the string has been accepted by the push down automata.

When we reach the acceptance state and find the stack to be empty, we say, the string has been accepted by the push down automata.

The next operation is performed by PDA considering three factors: present state,symbol on the top of the stack and the input symbol.