Originally Posted by

**Jagger** Ok thanks for your answer but I can't understand the meaning of functionally complete set of connectives.

As you said one connective y functionally complete when you can found a propositional formula formed in terms of NOT OR AND conectives equivalent to the other one...Is this true? or how can I know exactly when a connective or a set of connectives are functionally complete?

From the book of Dirk Van Dalen says "For each n-ary connective $ defined by its valuation function,

there is a proposition τ, containing only p1, . . . , pn, ∨ and ¬, such that

|= τ ↔ $(p1, . . . , pn). " but I don't understand the meaning of this Theorem