Eh, I'm not entirely sure here? QCD is an odd beast, one where at the same time you have gauge invariant gluon spin distribution, but no 3-direction projection of gluon spin can be gauge invariant by itself. Unfortunately, I only know enough to have semi-educated doubts about general statement. Discipline divided by common maths and insular lingo. SQMR is a shorthand for the "Consider the Hilbert space of quadratically integrable functions of positions phi(q), Integral[phi(q)^2, {q, R^n}] < Infinity..." you see in most textbooks. Still reading up on stuff though.Can we recover the same relationships between x and p if we give a treatment of, for example, how a quark interacts with a gluon? Obviously, the answer is yes. Doubly obvious, since we've unified the fields (...save gravity). Duh and sorry.
But SQMR (a special case of QMR?) sounds like a generalized version of this(?).