Difference between these two R functions

Question

I am trying to illustrate the three types of extreme value distributions in R.

For type one, the distribution function is as follows.

Answer 1

The problem is that the || operator only looks at the first element of z and z==b. This should work:

G2 <- function(z, a, b, alpha)
    ifelse(z<=b, 0,exp(-((z-b)/a)^(-alpha)))