A Bellman equation may be written as Vπ(s) = R(s,a,s') + γ ∑ P(s'|s,a) Vπ(s')
Q* plays a role in this equation, where Q* is the 'Optimal Function', S stands for 'State' and A refers to 'Action' in q∗(s′, a′)
q∗(s′, a′) are state-action pairs, fundamental to any Bellman equation, when moving from a current state (or given state) to the next state in a process.
This concludes our maths lesson because I'm not the mathematician required to explain any of this.