Manuscript XIX-D@1 · XIX-D.tex · remark · 1f47e33b
Remark: A sufficient product test is not a universal obstruction
Covariance, state selection, and quantum products › The classical Hessian is not its contraction · lines 497–504
The ordinary wavefront criterion excludes opposing covectors when defining a product by that calculus. Failure to meet a sufficient criterion does not by itself prove that every generalized or renormalized construction fails. Conversely, separate existence of the factors is not a proof of their ordinary product.