Thanks for your reply.
For the first part, if I use just the one state like below is it correct ? :
A_exist ({s1}, !s1, (!s1 & !p & !Xs1 | !s1 & p & Xs1 | s1 & !p & Xs1), Fs1)
For the second part:
I got your point by mistake I wrote disjunction, I will correct it.