Predicate Calculus statement I've been asked to write down a statement using predicate calculus and it is confusing me a great deal.
I've got statement A "no dog can fly" and B "There is a dog which can fly"
D = set of all dogs ,  F = set of all creatures that can fly
P(x) is the proposition that "creature x can fly"
Q(x) is the proposition that "creature x is a dog"
How do I write statements A and B using predicate calculus in terms of P(x)?
I wrote for A:  ∀x(P(x)→¬Q(x)  and  B: ∃x(P(x)→Q(x)
but this doesn't seem right to me at all.
Anyone got a suggestion?

The statement A is OK, apart from a missing parenthesis. Statement B should be something like $\exists x(Q(x)\land P(x))$.
Your version of B would be true if there were, for example, no flying creatures.
There are always many equivalent ways of stating things. Closer in tone to the English statement of A is $\forall x(Q(x)\longrightarrow \lnot P(x))$. Or maybe $\lnot\exists x(Q(x)\land P(x))$.
