For each of the following determine for each variable x the l x. it is bound to. I have numbered the variables and the abstraction. The variables are numbered using Arabic numerals and the abstractions. The variables are numbered using Arabic numerals and the abstraction are numbered using roman numerals. If variables 4 and 7 are bound to abstraction I, your answer should be of the form | 4,7 to indicate that abstraction I has variables 4, and 7 bound by it.

a. (lx. xx lx. x) x

I 1 2 II 3 4

b. lx. x x (lx. x) x

I 1 2 II 3 4 | | | 5 6 | V

c. lx. xx (lx. x) x lx. xx (lx. x) x

I 1 2 II 3 4 III 5 6 I V 7 8

d. lx. x x lx. x x lx. xx lx. x x

I 1 2 II 3 4 III 5 6 IV 7 8