Consider the satisfiability and validity properties of propositional logic statements. Which of the following

statements is definitely true?

Checking validity is NP$-$Complete while checking satisfiability can be done in polynomial time.

Both satisfiability and validity can be performed in polynomial time.

Both satisfiability and validity are NP$-$Complete.

Checking satisfiability is NP$-$Complete $($requires exponential time$),$ while checking validity can be done in

polynomial time.

What does the statement $F$ blue mean?

The atomic proposition blue holds in the next state.

The atomic proposition blue holds in some future state.

The atomic proposition blue never holds.

The atomic proposition blue holds in every state of a given path.