Rewrite the following using mathematical symbols:
a. Q is equal to the set whose elements are a, b, and c.
b. The set containing 1 and 3 only is a proper subset of the set of natural numbers.
c. The set containing 1 and 3 only is not a subset of {1,4,6,7}
d. The empty set does not contain 0 as an element.
a. Q = {a, b, c}
b. {1, 3} ⊂ ℕ
c. {1, 3} ⊄ {1, 4, 6, 7}
d. ∅ ≠ {0}