Identifiers may undergo a retention.Logical formLearned from8 sentences. An identifier can be actionable.Logical formLearned from8 sentences. A (user identifier) can be long-lived.Logical formLearned from8 sentences. An identifier may be specified.Logical formLearned from8 sentences. Identifiers may be linked to (cancer registries).Logical formLearned from8 sentences. (User identifiers) can be reliable.Logical formLearned from8 sentences. Sources may have unique identifiers.Logical formLearned from8 sentences. Some (data packets) may be marked with an identifier.Logical formLearned from8 sentences. An (instance identifier) can be forked.Logical formLearned from8 sentences. An identifier may remain constant.Logical formLearned from8 sentences. A (network address) of a host may serve as a (user identifier).Logical formLearned from8 sentences. An (identifier scheme) can be persistent.Logical formLearned from8 sentences. An identifier may pertain-to a station.Logical formLearned from8 sentences. Identifiers may be removed.Logical formLearned from8 sentences. An identifier can be popular.Logical formLearned from8 sentences.