17
Query Complexity
•
Proof
.
Recall the Satisfiability of Quantified
Boolean Formulas problem (QBF): is a QB
formula
F
true ?
•
•
Example:
F
=
9
X
1
8
X
2
8
X
3
(X
1
Æ
X
2
Ç
:
X
1
Æ
X
3
)
is it true ?
•
•
Note: boolean satisfiability (the NP-hard problem) is
in QBF [why ?]