Push Down Automata

Question

Which one is more powerful Deterministic push down automata or Non Deterministic push down automata ?

Answer 1

NPDA(Non Deterministic Push Down Automata) is more powerful than DPDA(Deterministic Push Down Automata).

for eg: There are languages for which we can make NPDA but DPDA can not be possible...

L = { WW^r   | W belongs to (a + b)^(+) }

Answer 2

expressive power of DPDA < expressive power of NPDA

ie. language accpeted by deterministic PDA is greater then Non deterministic PDA

therefore NPDA is more powerful then DPDA

Comments

is it right language accepted by pda is more than npda?

Answer 3

non deterministic push down automata is more powerfull