Collapsing a pair theorem
= Collapsing a pair theorem
For a good pair $(X,A)$, the quotient map induces natural isomorphisms
$$
H_q(X,A)\cong\widetilde H_q(X/A).
$$
= Collapsing a pair theorem
For a good pair $(X,A)$, the quotient map induces natural isomorphisms
$$
H_q(X,A)\cong\widetilde H_q(X/A).
$$