Stop show with sound -- Keyboard shortcut: 'x'  Next slide in show -- Keyboard shortcut: 'n'  3 minutes, 58 secondsThe Order of Evaluation - slide 10 : 26

The alpha rewrite rule
An alpha conversion changes the names of lambda expression formal parameters

Formal parameters of a lambda expression can be substituted by other names, which are not used as free names in the body

Legal conversion:
Expression

 Converted Expression

(lambda (x y) (f x y))
 
(lambda (a b) (f a b))
Illegal conversion:
Expression

 Converted Expression

(lambda (x y) (f x y))
 
(lambda (a f) (f a f))