Abstract
For submanifolds tangent to the structure vector field in
cosymplectic space forms, we establish a basic inequality between
the main intrinsic invariants of the submanifold, namely, its
sectional curvature and scalar curvature on one side; and its
main extrinsic invariant, namely, squared mean curvature on the
other side. Some applications, including inequalities between the
intrinsic invariant