Words can be abstract.Logical formLearned from221 sentences. Symbols can be abstract.Logical formLearned from221 sentences. Elements can be abstract.Logical formLearned from217 sentences. A world can be abstract.Logical formLearned from188 sentences. Sculptures can be abstract.Logical formLearned from187 sentences. Knowledge can be abstract.Logical formLearned from186 sentences. A system can be abstract.Logical formLearned from185 sentences. Questions can be abstract.Logical formLearned from183 sentences. A description can be abstract.Logical formLearned from182 sentences. An online can be abstract.Logical formLearned from171 sentences. A quality can be abstract.Logical formLearned from170 sentences. A view can be abstract.Logical formLearned from170 sentences. An approach can be abstract.Logical formLearned from168 sentences. A definition can be abstract.Logical formLearned from162 sentences. A method can be abstract.Logical formLearned from161 sentences.