a_even a_odd b_even b_odd acc ⊢, b a ⊣ a b a b a b ⊢
The machine as drawn — 5 states, 11 transitions.
The author’s examples, run aab → accept b → accept babab → accept ab → reject aabb → reject
Definition $$ \begin{aligned} M &= (Q, \Sigma, \delta, q_0, F) \\Q &= \{ \text{a\_even}, \text{a\_odd}, \text{b\_even}, \text{b\_odd}, \text{acc} \} \\\Sigma &= \{ \text{a}, \text{b} \} \\q_0 &= \text{a\_even} \\F &= \{ \text{acc} \} \\\delta &: Q \times (\Sigma \cup \{⊢, ⊣\}) \to Q \times \{L, R, S\} \end{aligned} $$
Verified by the library ✓ Tests pass — 5 examples checked ✓ Deterministic Machine code 2fa.ab:RBRARALC_RARB_LCLD_LDLCSZSize 5 states · 11 transitions Level Intermediate Licence Creative Commons Attribution 4.0 Tags showcase 2dfa