  The structural arrest of a polymeric suspension might be driven by an
increase of the cross--linker concentration, that drives the gel transition, as
well as by an increase of the polymer density, that induces a glass transition.
These dynamical continuous (gel) and discontinuous (glass) transitions might
interfere, since the glass transition might occur within the gel phase, and the
gel transition might be induced in a polymer suspension with glassy features.
Here we study the interplay of these transitions by investigating via
event--driven molecular dynamics simulation the relaxation dynamics of a
polymeric suspension as a function of the cross--linker concentration and the
monomer volume fraction. We show that the slow dynamics within the gel phase is
characterized by a long sub-diffusive regime, which is due both to the crowding
as well as to the presence of a percolating cluster. In this regime, the
transition of structural arrest is found to occur either along the gel or along
the glass line, depending on the length scale at which the dynamics is probed.
Where the two line meet there is no apparent sign of higher order dynamical
singularity. Logarithmic behavior typical of $A_{3}$ singularity appear inside
the gel phase along the glass transition line. These findings seem to be
related to the results of the mode coupling theory for the $F_{13}$ schematic
model.
