  Recently, we have shown that there do not exist the warped product semi-slant
submanifolds of cosymplectic manifolds [10]. As nearly cosymplectic structure
generalizes cosymplectic ones same as nearly Kaehler generalizes Kaehler
structure in almost Hermitian setting. It is interesting that the warped
product semi-slant submanifolds exist in nearly cosymplectic case while in case
of cosymplectic do not exist. In the beginning, we prove some preparatory
results and finally we obtain an inequality such as $\|h\|^2 \geq
4q\csc^2\theta\{1+\frac{1}{9}\cos^2\theta\}\|\nabla \ln f\|^2$ in terms of
intrinsic and extrinsic invariants. The equality case is also considered.
