Comment on “Decomposition of a Data Base and the Theory of Boolean Switching Functions” [Letter to the Editor]

Two of the authors of this letter have presented a theorem (Appendix C of [1], hereinafter called “Theorem C”) relating Codd's third normal form for a data collection [2] to the minimum cover for an associated Boolean function. Actually this theorem is incorrect as stated. The third author (Bernstein) in his dissertation [3] has produced a counterexample to the theorem and has developed techniques for decomposing a data base into third normal form under general conditions.