  We describe a general framework to depict the space of Lorentz invariant
effective field theories, which we call the landscape, given any kind of gauge
symmetry and field content. Various operator bases in the landscape can be
systematically constructed, with the help of amplitude-operator correspondence,
to emphasize different aspects: operator independence (y-basis), flavor
relation (p-basis) and conserved quantum number (j-basis). The transformation
matrices among the bases encode model-independent properties of the operators,
such as implications on their UV origin. We illustrate this salient feature in
examining the dimension 9 operators relevant for neutron-antineutron
oscillation.
