Let me define the following predicates:

O(x,y) means: "x owns y"

C(x) mean: "x is a car"

I want to translate these two sentences from English to FOL:

1) It isn't true that everyone owns a car

2) Either someone owns a car or no one owns a car

These are my proposed translations to FOL:


2) ∃x∃y(O(x,y)∧C(y)) ∨ ∀x¬∃y(O(x,y)∧C(y)

  • These seem like a series of homework questions, which aren't technically off-topic, but are somewhat frowned upon, since our goal here isn't to get people out of homework. Can you give a little more context for your interest in FOL, and your difficulty with these problems? Feb 15, 2016 at 16:11

1 Answer 1


These look correct to me, although the second is missing a close parenthesis. By the way, I believe the second one is a tautology.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .