Theory has no place is the real world -- even Codd knew that, and amended his 2-value system.
Besides, while you can get a way with '' (blank) for strings, you can't get away with "0" (zero) for integers. "No apples" isn't equivalent to "indeterminate number of applies".
But pretending that indeterminate values (a) don't exist, (b) don't need to be stored, and © have no place in the real world is just short-sighted.
Your "proofs" and "correctness" are ill-suited, where actual problems need to be solve, not addressed on a theoretical level and no further.
But if you're an experienced programmer, you know all of this, so why bother fighting?