For his "Algebra of Programming" John Backus used the function-level style, which avoided lambda variables. Functional programming, on the other hand, uses Lambda variables. Does it matter whether you use lambda variables for an "Algebra of Programming" or better not use them. Does the function-level style have advantages in this case or does it pose major problems in use?
I have the impression that John Backus' style makes the expressions of algebra clearer. On the other hand, lambda variables are more convenient to use and allow nesting of lambda terms.
