Not just Leibniz notation, but for example https://en.wikipedia.org/wiki/Partial_derivative is total bonkers, every single equation on it means the total opposite than in the rest of the mathematics.

Wtf is

> the partial derivation of a function f(x,y,z...)

or deriving a function respect to a variable? Functions don't have variables, named variables, that's Python, not math[0]. In math expressions can have free variables, and function arguments are indexed with numbers. You can derive x+y by x, or you can derive f : (x,y) |-> x+y by its first variable, but you can't mix them. That only leads to things as df(x,x)/dx and such abominations.

Multivariable calculus people really should just adopt the function notation of the rest of the mathematics fr.

[0] : https://en.wikipedia.org/wiki/Function_(mathematics)#Definit...