Problem $3$: $03\_$minus.lc

NOTE: You only need to write lambda$-$calculus definitions for SKIP$1,$ DECR, SUB, ISZ and EQL. If you modify any other other part of the file you will get $0$ points for the assignment.

PRO TIP: To test your definitions incrementally, replace undefined in the definitions of SKIP$1,$ DECR, SUB, ISZ and EQL with any syntactically valid lambda calc term. This should allow ELSA to parse the file so you can get results for the cases you are working on$.$

Part $($a$)(30$ points$)$

SKIP$1$ takes a function f and a pair p where the left$-$hand item in p indicates whether an application of f has been "skipped" yet. SKIP$1$ returns a pair p$\text{'}$ where the right$-$hand side of p$\text{'}$ equals f applied to the right$-$hand side of p$,$ but only if the left$-$hand item of p is TRUE, indicating an application of f has already been skipped.

Replace the definition of SKIP$1$ with a suitable lambda$-$term $($i$.$e$.$ replace undefined with a suitable term$)$ so that the below reductions are valid.