` ::: I just wanted to add that, as noted at Wikipedia talk:WikiProject Mathematics#‎Delta function, a quick Google search yields 320,000 results for Dirac AND ``Delta function``, compared to 78,800 results for Kronecker AND ``Delta function``; Google Books results yield 109,000 results for Dirac AND ``Delta function``, compared to 20,100 results for Kronecker AND ``Delta function``. In terms of Wikipedia primacy, last month Dirac delta function got 26741 hits, compared to Kronecker delta getting 6870 hits, and (just for the heck of it) Modular discriminant getting 115 hits. This is far and away enough for Dirac delta function to meet the WP:PRIMARY criteria of being a more substantial use than all other meanings combined.   `