A research team is training an agent and finds that two different reward functions, r_1 and r_2, lead to the agent learning the exact same optimal behavior. The relationship between the two functions is defined as r_2(s_t, a_t, s_{t+1}) = r_1(s_t, a_t, s_{t+1}) + f(s_t, a_t, s_{t+1}) for some non-zero function f. What is the most accurate explanation for this phenomenon?

Analyzing Reward Function Equivalence

Analyzing Reward Function Invariance