Which of the following is NOT a property of the ppp-adic norm?
∣x∣p≥0|x|_p \geq 0∣x∣p≥0
∣x+y∣p≤max(∣x∣p,∣y∣p)|x + y|_p \leq \max(|x|_p, |y|_p)∣x+y∣p≤max(∣x∣p,∣y∣p)
∣xy∣p=∣x∣p∣y∣p|xy|_p = |x|_p |y|_p∣xy∣p=∣x∣p∣y∣p
∣x+y∣p≤∣x∣p+∣y∣p|x + y|_p \leq |x|_p + |y|_p∣x+y∣p≤∣x∣p+∣y∣p and ∣x+y∣p=∣x∣p+∣y∣p|x + y|_p = |x|_p + |y|_p∣x+y∣p=∣x∣p+∣y∣p always