  We propose a way -- universal wave function overlap -- to extract universal
topological data from generic ground states of gapped systems in any
dimensions. Those extracted topological data should fully characterize the
topological orders with gapped or gapless boundary. For non-chiral topological
orders in 2+1D, this universal topological data consist of two matrices, $S$
and $T$, which generate a projective representation of $SL(2,\mathbb Z)$ on the
degenerate ground state Hilbert space on a torus. For topological orders with
gapped boundary in higher dimensions, this data constitutes a projective
representation of the mapping class group $MCG(M^d)$ of closed spatial manifold
$M^d$. For a set of simple models and perturbations in two dimensions, we show
that these quantities are protected to all orders in perturbation theory.
