The unfoldability conjecture for billiard triangles in Weyl chambers

Let ΔE\Delta\subset E be a Weyl chamber with tip at a special vertex oo. Let x0,xkΔx_0,x_k\in\Delta be special vertices, and consider a billiard triangle with geodesic sides ox0\overline{ox_0} and oxk\overline{ox_k} and broken side x0x1xk1xkx_0x_1\ldots x_{k-1}x_k. A billiard triangle is unfoldable when it can be unfolded to a geodesic triangle in the ambient symmetric space or building. It is a generalized Littelmann triangle when its broken side is a weak LS path, namely a broken geodesic satisfying Littelmann's axioms without requiring dist(λi1,λi)=1\operatorname{dist}(\lambda_{i-1},\lambda_i)=1 in the definition of an aa-chain.

Unfoldability conjecture. A billiard triangle in Δ\Delta with sides ox0\overline{ox_0}, oxk\overline{ox_k} and x0x1xk1xkx_0x_1\ldots x_{k-1}x_k, and with the special vertices 0,x0,xk0,x_0,x_k, is unfoldable if and only if it is a generalized Littelmann triangle.

This conjecture characterizes unfoldable billiard triangles through weak LS paths, extending the known correspondence between Littelmann triangles and tensor-product inclusions for representations of the dual group. The supplied source does not state whether the conjecture has been resolved.

Sources & referencesView supporting material

Primary source

Michael Kapovich, Bernhard Leeb and John J. Millson, “The generalized triangle inequalities in symmetric spaces and buildings with applications to algebra”, arXiv:math/0210256 (2005).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.