  We construct a seven-dimensional brane world in a slice of AdS_7, where the
boundary matter content is fixed by the cancellation of anomalies. The
seven-dimensional minimal N=2 gauged supergravity is compactified on the
orbifold S^1/Z_2, and the supersymmetric bulk-boundary Lagrangian is
consistently derived for boundary vector and hypermultipets up to fermionic
bilinear terms. Anomaly cancellation then fixes the boundary gauge coupling in
terms of the seven-dimensional Planck mass, and a topological mass parameter of
the Chern-Simons term. In addition for gauge groups containing the standard
model, anomaly cancellation restricts the gauge groups on the six-dimensional
boundaries to be only one of the exceptional groups. There are also special
values of the separation of the two boundaries, where the boundary couplings
become singular, and lead to a possible phase transition in the boundary
theory. Furthermore, by the AdS/CFT correspondence our brane world is dual to a
six-dimensional conformal field theory, suggesting that our bulk theory
describes the strong coupling dynamics of six-dimensional theories.
