FSM: where

Vin={a} V i n = { a } , Vout={o} , Vstate={p,q} , I = p ∨ q , R = next(p)|o&a&!q<->next(q)<->p

How can I compute the existential predecessors of **p<->!q? **And How the left associativity is distributed among relation R [ Is it the right way to give brackets " ((next(p)|(o&a&!q))<->(next(q))<->p)" ? ]