The space CN has no free analogue, but we can talk instead about
the free sphere SC,+N−1​, as the manifold defined by the
equations ∑i​xi​xi∗​=∑i​xi∗​xi​=1. We discuss here the structure and
hierarchy of the submanifolds X⊂SC,+N−1​, with particular
attention to the manifolds having an integration functional tr:C(X)→C.Comment: 400 pages. arXiv admin note: text overlap with arXiv:1909.0815