Recently, Choi and Lu proved that the Wintgen inequality ? ? H2??? +k, (where
? is the normalized scalar curvature and H2, respectively ??, are the
squared mean curvature and the normalized scalar normal curvature) holds on
any 3-dimensional submanifold M3 with arbitrary codimension m in any real
space form ~M3+m(k) of curvature k. For a given Riemannian manifold M3, this
inequality can be interpreted as follows: for all possible isometric
immersions of M3 in space forms ~M3+m(k), the value of the intrinsic
curvature ? of M puts a lower bound to all possible values of the extrinsic
curvature H2 ? ?? + k that M in any case can not avoid to ?undergo" as a
submanifold of ?M. From this point of view, M is called a Wintgen ideal
submanifold of ~M when this extrinsic curvature H2 ??? +k actually assumes
its theoretically smallest possible value, as given by its intrinsic
curvature ?, at all points of M. We show that the pseudo-symmetry or,
equivalently, the property to be quasi-Einstein of such 3-dimensional
Wintgen ideal submanifolds M3 of M~3+m(k) can be characterized in terms of
the intrinsic minimal values of the Ricci curvatures and of the Riemannian
sectional curvatures of M and of the extrinsic notions of the umbilicity,
the minimality and the pseudo-umbilicity of M in ~M.