EntityQ1297858· pop 7· linked from 2 articlesClass logicSign in to saveConnectionslogicEntityBertrand RussellEntityInternational Standard Book NumberEntityset theoryEntitycalculusEntityGottlob FregeEntityGiuseppe PeanoEntityWillard Van Orman QuineEntityRussell's paradoxEntityantinomyEntityErnst ZermeloEntityfirst-order logicEntityPeano axiomsEntityformal systemEntitynaive set theoryEntityclassEntityZermelo–Fraenkel set theoryEntitytype theoryEntityaxiom of extensionalityEntityCesare Burali-FortiEntityCategoriesMathematical logicSet theory