| 1x | | matrix convex set, matrix extreme point, matrix exposed point, Krein-Milman theorem, Straszewicz-Klee theorem, matrix face, matrix exposed face, free spectrahedron, $\Gamma$-convex set, $\Gamma$-operator system, $\Gamma$-ucp map, free extreme point, $\Gamma$-extreme point, Weyl algebra, noncommutative valuations, skew polynomial rings, orderings, extensions of valuations, extensions of orderings., Noncommutative rational invariants, noncommutative Noether’s problem, automorphisms of free skew-field |