  N=2 noncritical strings are closely related to the $\Slr/\Slr$ Wess-Zumino-
Novikov-Witten model, and there is much hope to further probe the former by
using the algebraic apparatus provided by the latter. An important ingredient
is the precise knowledge of the $\hslc$ representation theory at fractional
level. In this paper, the embedding diagrams of singular vectors appearing in
$\hslc$ Verma modules for fractional values of the level ($k=p/q-1$, p and q
coprime) are derived analytically. The nilpotency of the fermionic generators
in $\hslc$ requires the introduction of a nontrivial generalisation of the MFF
construction to relate singular vectors among themselves. The diagrams reveal a
striking similarity with the degenerate representations of the $N=2$
superconformal algebra.
