Nitpick squared: http://en.wikipedia.org/wiki/Derivation_(differential_algebra) http://en.wikipedia.org/wiki/Derivation_(differential_algebr... When I first le

Nitpick squared: http://en.wikipedia.org/wiki/Derivation_(differential_algebra) http://en.wikipedia.org/wiki/Derivation_(differential_algebr... When I first learned this in a graduate abstract algebra class, however, I was convinced that my professor, who was not a native English speaker, was simply mistranslating from whatever language he was used to talking about these things in. (He was, IIRC, a Romanian, educated in Germany.)