  Using effective field theory we derive inequalities for light nuclei in the
Wigner symmetry limit. This is the limit where isospin and spin degrees of
freedom can be interchanged. We prove that the energy of any three-nucleon
state is bounded below by the average energy of the lowest two-nucleon and
four-nucleon states. We show how this is modified by lowest-order terms
breaking Wigner symmetry and prove general energy convexity results for SU(N).
We also discuss the inclusion of Wigner-symmetric three and four-nucleon force
terms.
