I just stuck upon a discrete maths-related problem with proving that a set of logical connectives is complete. I already know how to prove that ("basic") sets are full (examples like show that the given set of connectives is complete: $\{\lnot, \Rightarrow\}$), but I got stuck upon the following example...
Three-figure logical connective $W(p,q,r)$ is defined as $W(p,q,r) \equiv (p \lor q) \Rightarrow \lnot r$. Proove that set $\{W\}$ is a complete set of connectives.
What should I do here? I know that a known complete set is $\{\lnot, \land, \lor\}$ and that I should "derive" each one of those connectives with $(p \lor q) \Rightarrow \lnot r$, but how should I even start?
P.S.: I'm sorry if the translation of the assignment isn't 100% accurate, because English is not my first language and this assignment is given in my native language :)