I want to know how to prove or disprove:
- For all integers $a, b$, we have $\text{gcd}(a,b)\le\min(a,b)$
- For all integers $a, b$, we have $\text{gcd}(a,b)\le\min(|a|,|b|)$
- For all non-zero integers $a, b$, we have $\text{gcd}(a,b)\le\min(|a|,|b|)$.
This is everything I want to know. Thank you.