Poincare duality
= Poincare duality
{c}
{wiki}
For a closed oriented $d$-manifold, cap product with the fundamental class gives isomorphisms
$$
H^k(M;R)\cong H_{d-k}(M;R).
$$
= Poincare duality
{c}
{wiki}
For a closed oriented $d$-manifold, cap product with the fundamental class gives isomorphisms
$$
H^k(M;R)\cong H_{d-k}(M;R).
$$