The obstruction theorem

Over a formal power-series ring, forcing $\hslash 1=0$ does not by itself force $1=0$. It may produce an $\hslash$-torsion quotient, including a classical specialization. After inverting $\hslash$, however, it forces the zero algebra. Neither option is the intended coefficientwise quantum restriction.

The inherited equation ideal remains valid. The obstruction is caused by adding a new condition which the causal contractions do not annihilate. Thus it is not a contradiction of XII-A's full-shell descent theorem. A smaller observable algebra, different constraint implementation, or separately proved reduction is not excluded by this argument.