A deterministic state machine is a computational model where the next state and output are uniquely determined by the current state and input, following well-defined transition rules. It exhibits predictable behavior, with no ambiguity in state transitions.

State transition functions are mathematical or logical rules that define how a system or process moves from one state to another based on input or current state. They determine the behavior, outputs, or changes in a deterministic manner, encapsulating the system's dynamics.