  It is shown that the multiquark gauge-invariant operators can, in general, be
decomposed into combinations of products of ordinary hadronic operators,
exhibiting their cluster reducibility. The latter property inhibits the
formation of completely compact multiquark bound states. Multiquark operators
still play a crucial role in the description of exotic states in regions of
configuration space where the hadronic clusters are close to each other. Our
proof gives a foundation for a unified viewpoint, where the multiquark-type and
the molecular-type approaches play complementary roles, at the gauge-invariant
nonlocal operator level.
