4andtherelativecohomologygroupsHXnXiHerearethefoursequenceslinedupforcomparisonHXHX1HXn1HXnHXHX1 HXn1 HXnHX1XHXnHXnX1HXnXn1HX1X ID: 341306
4andtherelativecohomologygroupsH(Xn;Xi).Herearethefoursequences