Invariant trilinear forms for SL(3,R)

Abstract

We give a detailed analysis of the orbit structure of the third power of the flag variety attached to SL(3,R). It turns out that 36 generalized Schubert cells split into 70 orbits plus one continuous family of orbits. On the latter, we construct invariant distributions and thus fill a gap in the literature by giving infinitely many linearly independent triple products of induced representations.