$15\mathrm{.}6$: Turing Machine Definitions

Let M be a Turing machine with states including p and q and a tape alphabet including a and b$.$

Assume that M$$s transition function $\backslash$delta has $\backslash$delta $($p$,$ a$)=($q$,$ b$,$ R$).$

Then when M sees an a while in state p$,$ it first moves to the right, then overwrites the character there with the letter b$.$