If avocados are not both sold at the local farmers market in New Haven and shipped from Columbia, then they are neither sold at the local farmers market in New Haven nor in New Haven generally.
¬(SoldAt(avocado, localFarmersMarket) ∧ ShippedFrom(avocado, colombia)) → ¬SoldAt(avocado, localFarmersMarket) ∧ ¬SoldIn(avocado, newHaven)