δij = 1 if i=j, 0 otherwise.
If you’re going to declare such a trivial operator part of the standard notation, at least don’t name it after someone as if it were a groundbreaking novelty!
Also see Iverson brackets, a similar operator named after the creator of APL who received a Turing award in part “for his contributions to mathematical notation” (hopefully more because he created APL; most creators of popular programming languages have won Turing awards).