theorem gcd02 (a: nat): $ gcd a 0 = a $;
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | eqtr | gcd a 0 = gcd 0 a -> gcd 0 a = a -> gcd a 0 = a |
|
2 | gcdcom | gcd a 0 = gcd 0 a |
|
3 | 1, 2 | ax_mp | gcd 0 a = a -> gcd a 0 = a |
4 | gcd01 | gcd 0 a = a |
|
5 | 3, 4 | ax_mp | gcd a 0 = a |