EntityQ1890389· pop 13· linked from 168 articlesconnected sumSign in to savegeometric modification on manifoldsConnectionsmathematicsEntityInternational Standard Book NumberEntitycircleEntitytopologyEntitysphereEntitymathematical proofEntitydigital object identifierEntitygroupEntitysurfaceEntitytorusEntityisomorphismEntitymanifoldEntityhomeomorphismEntityballEntityidentity elementEntityunit vectorEntitymonoidEntitynormalEntitydisjoint setsEntityneighborhoodEntityCategoriesDifferential topologyGeometric topologyKnot theoryOperations on structures