State transitions are the cornerstone of finite automata. They describe how an automaton moves from one state to another based on input symbols.
In our NFA example, the transitions are clearly defined by the input alphabet of {a, b}. The initial state is q0, and as the automaton reads the input, it transitions between various states according to predefined rules.
- From q0, reading 'a' leads back to q0, and reading 'b' transitions it to q1.
- At state q1, reading 'a' goes to q2, while reading 'b' stays at q1.
- From q2, reading 'a' remains in q2, but 'b' takes it to the accept state.
- Once at the accept state, any further input keeps it in that state.
These transitions ensure that the automaton can "keep track" of its progress in recognizing the sequence "bab".