A concept can be valid.Logical formLearned from4 sentences. An (email message) can be valid.Logical formLearned from4 sentences. A statistic can be valid.Logical formLearned from4 sentences. Vouchers can be valid.Logical formLearned from4 sentences. A referral can be valid.Logical formLearned from4 sentences. A transfer of (copyright ownership) can be valid.Logical formLearned from4 sentences. An (animal model) can be valid.Logical formLearned from4 sentences. An axiom can be valid.Logical formLearned from4 sentences. Forecasts can be valid.Logical formLearned from4 sentences. Ratings can be valid.Logical formLearned from4 sentences. A log can be valid.Logical formLearned from4 sentences. Teachers can be valid.Logical formLearned from4 sentences. A book can be valid.Logical formLearned from4 sentences. Inference can be valid.Logical formLearned from4 sentences. An (account string) can be valid.Logical formLearned from4 sentences.