How can I combine 2 PDA's into 1 I need to form PDA for this language: {$a^nb^m|n=m \vee n=2m$}
I know the idea of building each one separately but how do I combine them into 1 PDA?
LHS: for every 'a' I push 'A' inside stack and for every 'b' I eject 'A'.
RHS:for every 'a' I push 'A' inside stack and for every 'b' I eject 2 times 'A'.
How can I combine them? Can I somehow use non determinism?
Construct one PDA for $n=m$ and another one for $n=2m$. Branch to one of them using an $\epsilon$ transition at the very beginning.