EntityQ371983· pop 36· linked from 308 articlesindicator functionSign in to savefunction that returns 1 if an element is present in a specified subset and 0 if absent; naturally isomorphic with a set's subsetsConnectionssubsetEntityDirac delta functionEntitymathematicsEntitystatisticsEntityGreek alphabetEntityInternational Standard Book NumberEntityWikidataEntityfunctionEntitynumber theoryEntityreal numberEntityrational numberEntitysetEntityKurt GödelEntitydigital object identifierEntityInternational Standard Serial NumberEntityprobability theoryEntitycombinatoricsEntityrandom variableEntityvarianceEntityalgebraic geometryEntityCategoriesBasic concepts in set theoryIntegral calculusMathematical logicMeasure theoryProbability theoryReal analysisTypes of functions