  Mixed 3-structures are odd-dimensional analogues of paraquaternionic
structures. They appear naturally on lightlike hypersurfaces of almost
paraquaternionic hermitian manifolds. We study invariant and anti-invariant
submanifolds in a manifold endowed with a mixed 3-structure and a compatible
(semi-Riemannian) metric. Particular attention is given to two cases of ambient
space: mixed 3-Sasakian and mixed 3-cosymplectic.

Differential Geometry