  The main result of this article is the decomposition of tensor products of
representations of SL(2) in the sum of irreducible representations parametrized
by outerplanar graphs. An outerplanar graph is a graph with the vertices 0, 1,
2, ..., m, edges of which can be drawn in the upper half-plane without
intersections. I allow for a graph to have multiple edges, but don't allow
loops.
