{"id":"gcd-reduces-common-factor-counting","text":"`common_factors(a, b)` converts the two-variable problem into divisor-counting on `gcd(a, b)`, since the set of common factors of (a, b) equals the set of divisors of gcd(a, b)","truth_value":"IN","source":"entries/2026/06/06/number-of-common-factors-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"gcd-reduces-common-factor-counting","truth_value":"IN","reason":"premise"}]}}