Updated evidence about the inherited definition

Agreement of two extensions on ${\mathcal{D}}_{\mathrm{int}}$ alone would not prove agreement at $F_{\mathrm{co}}$. Agreement as smooth zero-data Cauchy solutions does prove it.

For comparison, the integral on the right of (eq:direct-conditional) exists independently of the hypothesis of Proposition prop:coordinate-compatibility. When independently defined it is denoted $I_{\mathrm{cand}}$. Its existence does not silently identify it with the inherited completion.