2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/73177We investigate Bar-Natan's characteristic two Khovanov link homology theory studying both the filtered and bi-graded theories. The filtered theory is computed explicitly and the bi-graded theory analysed by setting up a family of spectral sequences. The E_2-pages can be described in terms of groups arising from the action of a certain endomorphism on mod 2 Khovanov homology. Some simple consequences are discussed.18 pages, 12 figures; substantially re-written; now includes reduced theory; hypothesis removed from applicationGeometric TopologyQuantum Algebra57M25text