Let's assume I have the closure

`F <- function(a, b) { function(x) { a*x^b } }`

and I want to create a sum G of F-functions

G(x, y, z) = F_1(x) + F_2(y) + F_3(z)

that depends on several variables (not just x). **However**, F_2 should not depend on x for example.

For start, I would use a function that adds together a list of functions:

`addFunctions <- function(x, l) { # x variable # l list of functions sum(sapply(l, function(f) f(x))) }`

I start by defining the F-functions and

`F_1 <- F(1, 2) F_2 <- F(3, 4) F_3 <- F(4, 5)`

`G <- function(x) {addFunctions(x, list(F_1, F_2, F_3))}`

However, this would only give me a function G of one variable x.

Why wouldn't I just define the sum directly? Well, because the case I really have is much more complicated and the number of independent variables may vary.

Any suggestions?