Let B(x) mean “x is a bird”,
let W(x) mean “x is a worm”,
let E(x, y) mean “x eats y”.
There is a statement "Only birds eat worms".
If we translate this statement to predicate formula it will become: $∀x∀y(W(x) ∧ E(y, x) → B(y))$
I was wondering will it be the same as $∀x∀y(B(x) ∧ E(x, y) → W(y))$ ?
Anything will be a bird if it eats anything which is a worm.
Any eater of worms is a bird.
Only birds eat worms.
Anything will be a worm if it is eaten by anything which is a bird.
Only worms are eaten by birds.