## Main Assumption

**In this talk**,
$A$
is an
$NP$-predicate,
that is:

- $y \in A(x,\_)$
can be tested in
*polynomial time*. - $y$
is of size
*polynomial*in the size of $x$.

Many natural problems have this property:

- Enumerate the
*answer set*of a**database query $Q$ on database $\mathbb{D}$** - Enumerate the
*transversals*of a**hypergraph $\mathcal{H}$**