What's the negation of “At least three of the sentence are false”? Following with the question I asked before
What's the negation of "One of the sentence is false"?
The negation of “At least three of the sentence are false” would be "any, one or two of the sentence is/are false"?

The negation of “At least three of the sentence are false” is "At most two of the sentences are false".
Assuming variables range over sentences, the "at least three" statement can be represented by 
$$
\exists x,y,z(False(x)\land False(y)\land False(z)\land x\ne y \land x\ne z \land y\ne z).
$$
Its negation is (equivalent to)
$$
\forall x,y,z(False(x)\land False(y)\land False(z)\to x=y \lor x=z \lor y=z).
$$
