If Emily does not both own at least one pet and lives in apartments in big metropolitan cities, then Emily either owns at least one pet and lives in an apartment in big metropolitan cities, or she neither owns a pet nor lives in an apartment in big metropolitan cities.
((∃y (Own(emily, y) ∧ Roommate(y))) ∧ LiveIn(emily, apartment, bigMetropolitanCity)) → ((∃y (Own(emily, y) ∧ Pet(y))) ∧ LiveIn(emily, apartment, bigMetropolitanCity)) ⊕ ¬((∃y (Own(emily, y) ∧ Roommate(y))) ∨ LiveIn(emily, apartment, bigMetropolitanCity))