{"id":"seen-set-monotonic","text":"The `seen` vowel set within each inner loop iteration is monotonically non-decreasing; once all 5 vowels are found, every further vowel-only extension also increments the count","truth_value":"IN","source":"entries/2026/06/06/count-vowel-substrings-of-a-string-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"seen-set-monotonic","truth_value":"IN","reason":"premise"}]}}