You have to prove it$.$ Given a definition of an abstraction as provided, you have to prove the statement which asserts that it behaves like beta reduction, but in Controll Language.

${}_{2}x*x-=SKK,$

${}_{2}x*P-=KPifx!$inFV$(P),$

${}_{2}x*Px-=Pifx!$inFV$(P),$

${}_{2}x*PQ-=S({}_{2}x*P)({}_{2}x*Q)$

${}_{2}x.PQ-=S({}_{2}x.P)({}_{2}x.Q),if$ the previous cases $do$ not apply.

Prove $CL|--({}_{2}x*P)Q|]=[Q.$