  In this paper, using computations done through the LiE software, we compare
the tensor product of irreducible selfdual representations of the special
linear group with those of classical groups to formulate some conjectures
relating the two. In the process a few other phenomenon present themselves
which we record as questions.
  More precisely, under the natural correspondence of irreducible finite
dimensional selfdual representations of ${\rm SL}_{2n}({\mathbb C})$ with those
of ${\rm Spin}_{2n+1}({\mathbb C})$, it is easy to see that if the tensor
product of three irreducible representations of ${\rm Spin}_{2n+1}({\rm C})$
contains the trivial representation, then so does the tensor product of the
corresponding representations of ${\rm SL}_{2n}({\rm C})$. The paper formulates
a conjecture in the reverse direction. We also deal with the pair $({\rm
SL}_{2n+1}({\rm C}), {\rm Sp}_{2n}({\rm C}))$.
