The pushdown automation $M=(\left\{q_{0}, q_{1}, q_{2}\right\}, \left\{a, b\right\}, \left\{0, 1\right\}, \delta, q_{0}, 0, \left\{q_{0}\right\})$ with
$\delta (q_{0}, a, 0)= \left\{(q_{1}, 10)\right\}$
$\delta (q_{1}, a, 1)= \left\{(q_{1}, 11)\right\}$
$\delta (q_{1}, b, 1)= \left\{(q_{2}, \lambda)\right\}$
$\delta (q_{2}, b, 1)= \left\{(q_{2}, \lambda)\right\}$
$\delta (q_{2}, \lambda, 0)= \left\{(q_{0}, \lambda)\right\}$
Accepts the language
- $L=\left\{a^{n}b^{m} | n, m \geq 0\right\}$
- $L=\left\{a^{n}b^{n} | n \geq 0\right\}$
- $L=\left\{a^{n}b^{m} | n, m > 0\right\}$
- $L=\left\{a^{n}b^{n} | n > 0\right\}$