Like the function RESQ_IMP_RES_THEN, the function RESQ_RES_THEN
performs a single step resolution. The difference is that the
restricted universal quantification used in the resolution is taken
from the assumptions.
Given a theorem-tactic ttac, applying the tactic
RESQ_RES_THEN ttac to a goal (asml,gl) has the effect of:
   MAP_EVERY (mapfilter ttac [... ; (ai,aj |- vi) ; ...]) (amsl ?- g)