Arguments in lambda expressions

Question

In a book I encountered the following lambda expression

(λabc.cba)zz(λwv.w)

How should I interpret the arguments of (λabc.cba)? Are there two arguments

(zz)(λwv.w)

or are there three arguments

(z)(z)(λwv.w)

I suspect three arguments since normally one letter is used in Mathematics to denote a variable (unlike from in programming).

Answer 1

Are there two arguments or are there three arguments?

Three arguments

If don't explicit add parentheses to zz as (zz) , the application associate to the left as below:

( ( (λabc.cba) z) z) (λwv.w)

It is equivalent to take three arguments.