I have attempted to translate the English sentence "the very best candy is chocolate" into predicate logic as follows: $$\lnot \exists x \exists y[(C_x \land \lnot C_y)\to B_{yx} ]$$ where $x$ and $y$ are candies, $C_x:x$ contains chocolate, and $B_{xy}:x$ is better than $y$.
However, the text I am using translates it as follows: $$\exists x[C_x \land \lnot \exists y(B_{yx})].$$
So my question is, is my translation equivalent to the one in the text? I am inclined to believe that my translation is simply a less concise rephrasing of the same idea, but I would like to be sure.
Edit: I think I understand it now. It is possible that I misunderstood the sentence as saying all candies containing chocolate are better than those which do not, instead of the alternative the very best candy is one which contains chocolate.
These are not mathematically equivalent. The key to seeing this is that yours has a non-trivial dependency on the value of $C_y$. We can rephrase yours as $\forall x\forall y[(C_x\land\neg C_y\land\neg B_{yx})]$ and the other as $\exists x\forall y(C_x\land\neg B_{yx})$ which might make things formally clearer.
Looking at this from an English point of view, your statement is "It is not the case that there exists two candies such that $x$ contains chocolate $y$ does not, and $y$ is better than $x$" while the book statement is "the candy that is the best contains chocolate"