2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/78404A formula for the difference of Vassiliev invariants of degree k+1 of two knots all of whose Vassiliev invariants of degree k agree is proven. The proof uses K. Habiro's C-moves and his theorem which relates them to Vassiliev invariants.12 pages, AMS-LaTeX, 12 figures. Write-up of part of a talk given in the Topology Seminar of the Max-Planck Institute for Mathematics. Typos and oversights (Statement of Theorem) are dealt with, Final comment and reference addedGeometric Topology57M25text