Valid point, but I will also amend your nitpick: Schwarz is also a name of a lot of people :) Both refer to hair colour, I think. "Schwartz" was a valid spellin

Valid point, but I will also amend your nitpick: Schwarz is also a name of a lot of people :) Both refer to hair colour, I think. "Schwartz" was a valid spelling for the colour many centuries ago (see, e.g., item 15 in [1]), which makes sense since both spellings are pronounced the same way. Surnames don't follow spelling changes, so that's the only situation in which both variants coexist now. In maths, you have the Cauchy-Schwarz inequality and Schwartz's theory of distributions. [1] https://woerterbuchnetz.de/?sigle=DWB&lemid=S04549 https://woerterbuchnetz.de/?sigle=DWB&lemid=S04549