A pair (R, F) of a temporal relation schema R and a set of associated temporal functional dependencies F is in temporal Boyce-Codd normal form (TBCNF) if
Similarly, (R, F) is in temporal third normal form (T3NF) if for all non-trivial temporal functional dependencies XY in F+, X is a temporal superkey for R or each attribute of Y is part of a minimal temporal key of R.
The definition of temporal fourth normal form (T4NF) is similar to that of TBCNF, but also uses temporal multivalued dependencies.