n=2: Lambda dim 4; tau^2=1: True
   E_eps    : dim ker D over modes box = 4 (tau+ 2, tau- 2); min |eig| = 2.571e-17
   f^*E_eps : dim ker D over modes box = 0 (tau+ 0, tau- 0); min |eig| = 5.000e-03
n=4: Lambda dim 16; tau^2=1: True
   E_eps    : dim ker D over modes box = 16 (tau+ 8, tau- 8); min |eig| = 7.790e-16
   f^*E_eps : dim ker D over modes box = 0 (tau+ 0, tau- 0); min |eig| = 5.000e-03
