1) Compute the set of states that satisfy AG(EXb ∨ E [c SB c])
2) Compute the set of states that satisfy EX(E [b SU a] ∨ A [c U c])
In question 1, the solution says the formula [c SB c] is false, because c before c is an invalid condition. Hence we ignore it.
In question 2, the solution says A [c U c] is just A(c).
I was confused why this holds because c weak until c seems false but i think it is true because in a U b, Ga satisfies it