EntityQ859254· pop 5· linked from 330 articlessubstructureSign in to savesubset of a structure that itself forms a structureConnectionssemantic theory of truthEntitymathematical logicEntitymonoidEntityfirst-order logicEntityformal systemEntityalgebra over a fieldEntityrecursive setEntitysemantics of logicEntityelementary equivalenceEntitystructureEntityConservative extensionEntitydiagramEntityground expressionEntitylogicEntityInternational Standard Book NumberEntitycomplex numberEntityset theoryEntityfunctionEntityreal numberEntityrational numberEntityCategoriesMathematical logicModel theoryUniversal algebra