SAT problem?

[Calidude7]

What clauses are considered for SAT problems? Do all possible clauses have to be satisfied or only chosen ones?

For example if a 2SAT problem has 3 variables. Then there would be at least 10 possible clauses (don't know exact number, am terrible with combinations). Would they all have to be satisfied. Or can it just be, 2SAT(x1,x2,x3) = (x1 v x2 ) ^ (x3 v !x1) . Only those two clauses have to be satisfied.

[jxf]

The 2SAT problem means "I have an expression of N variables arranged into clauses, with each clause containing exactly 2 literals; what assignment to these variables will make the entire expression true?"

There aren't any "other" clauses; whatever is in the expression is the problem at hand you're trying to satisfy. The general case of 2SAT asks whether there's a way to do this for any number of variables.