REFERENCES:
+ .. [HilgertHofmannLawson] Joachim Hilgert, Karl Heinrich Hofmann, and Jimmie
+ D. Lawson. Lie groups, convex cones and semigroups. Oxford Mathematical
+ Monographs. Clarendon Press, Oxford, 1989. ISBN 9780198535690.
+
.. [Tam] Bit-Shun Tam. On the duality operator of a convex cone. Linear
Algebra and its Applications, 64:33-56, 1985, doi:10.1016/0024-3795(85)
90265-4.