EntityQ6516731· pop 6· linked from 25 articlesLefschetz hyperplane theoremSign in to savetheorem that the inclusion between a projective variety and its hyperplane section induces isomorphisms of homology, cohomology or homotopy groups in low degreesConnectionscohomologyEntityMorse theoryEntitymathematicsEntityInternational Standard Book NumberEntitydigital object identifierEntityInternational Standard Serial NumberEntityJSTOROrganizationalgebraic geometryEntityAlexander GrothendieckEntityalgebraic topologyEntityCambridge University PressEntityRené ThomEntityJohn MilnorEntityPierre DeligneEntityKunihiko KodairaEntityQ22908627Entityalgebraic varietyEntitySpringer Science+Business MediaEntityPrinceton University PressEntityhomologyEntityCategoriesMorse theoryTheorems in algebraic geometryTheorems in algebraic topologyTopological methods of algebraic geometry