Term for functions that map functions to other functions
The usual term for those "functions" is the term "operator". For example, the operator $T$ that "swap" coordinates is defined by $T(f) = g$ with $g(x,y) = f(y,x)$.
The usual term for those "functions" is the term "operator". For example, the operator $T$ that "swap" coordinates is defined by $T(f) = g$ with $g(x,y) = f(y,x)$.