DirtyMortI'm a math major, and when school started to actually get enjoyable for me, it was under the guidance of a wonderful calculus prof who'd become a mentor of mine. When I was in calc 2, I was also in a field research class and realized that a problem we were having with developing an experiment could basically be solved with an optimization problem, only with multiple independent variables. This is a calc 4 concept, but my mentor helped me get started on learning it on my own and showed a lot of faith in my ability. It was really empowering, so the gradient vector and calculus in general hold a really special place in my heart.
Hence, Differ ∇ = Differ-Del = just a vague nod to calculus and particularly, the gradient vector. :)
https://jeremykun.files.wordpress.com/2013/11/gradient.gif
wtf is your problem? can you stop harassing people on the internet... seriously get a life...