Binary operations and algebraic structures
General · Mathematics
Study notes
Q: Is subtraction a binary operation on ℕ? On ℤ? Is it associative? ℕ: 3-5 = -2 ∉ ℕ: NOT closed - not a binary op on ℕ! ℤ: always in ℤ: binary operation ✓! Associative? (5-3)-2 = 0; 5-(3-2) = 4: NOT associative! (Closure first, then properties!)