The null defect in the one source-complete module

The only module in the record for which presentations, reconstruction, canonical domain, and target are all defined is XV-C's finite normal-jet module. XV-C computed its full reconstruction kernel. XV-D now carries out, for this module, the full D1–D2 programme: define the preliminary lifts, compute their null defects, locate the defects, and test cancellation. Everything below is for this module. It is not identified with ${\mathcal{P}}_{\mathrm{int}}$.