A frequency may pertain-to a carrier.Logical formLearned from18 sentences. A carrier can be digital.Logical formLearned from18 sentences. A carrier may return to a US-city.Logical formLearned from18 sentences. A carrier can be at a US-city.Logical formLearned from18 sentences. Use can be by carriers.Logical formLearned from18 sentences. Carriers can be from countries.Logical formLearned from18 sentences. A carrier can be with (market power).Logical formLearned from18 sentences. A failure may pertain-to a carrier.Logical formLearned from18 sentences. A use may pertain-to carriers.Logical formLearned from18 sentences. A use may pertain-to a carrier.Logical formLearned from18 sentences. (International carriers) may pertain-to a country.Logical formLearned from18 sentences. A (carrier regulation) can be dominant.Logical formLearned from18 sentences. Carriers may pertain-to a disorder.Logical formLearned from18 sentences. Carriers can be constituted-of-or-filled-with passengers.Logical formLearned from18 sentences. Carriers can be inefficient.Logical formLearned from18 sentences.