| ⊦ gcd(m, gcd(n, n0)) | gcd(gcd(m, n), n0) ∧ gcd(gcd(m, n), n0) | gcd(m, gcd(n, n0)), gcd(m, gcd(n, n0)) = gcd(gcd(m, n), n0) |
⊦ gcd(m, gcd(n, n0)) | gcd(gcd(m, n), n0), gcd(m, gcd(n, n0)) = gcd(gcd(m, n), n0)
⊦ gcd(gcd(m, n), n0) | gcd(m, gcd(n, n0)), gcd(m, gcd(n, n0)) = gcd(gcd(m, n), n0)